diff --git a/.github/workflows/ci-runnerpg.yml b/.github/workflows/ci-runnerpg.yml
index ab261b3f1..cdf1d5751 100644
--- a/.github/workflows/ci-runnerpg.yml
+++ b/.github/workflows/ci-runnerpg.yml
@@ -215,6 +215,8 @@ jobs:
         import static org.postgresql.pljava.packaging.Node.stateMachine;
         import static org.postgresql.pljava.packaging.Node.isVoidResultSet;
         import static org.postgresql.pljava.packaging.Node.s_isWindows;
+        import static
+            org.postgresql.pljava.packaging.Node.NOTHING_OR_PGJDBC_ZERO_COUNT;
         /*
          * Imports that will be needed to serve a jar file over http
          * when the time comes for testing that.
@@ -339,7 +341,9 @@ jobs:
               // state 1: consume any diagnostics, or to state 2 with same item
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
 
-              // state 2: must be end of input
+              NOTHING_OR_PGJDBC_ZERO_COUNT, // state 2
+
+              // state 3: must be end of input
               (o,p,q) -> null == o
             );
           }
@@ -566,6 +570,9 @@ jobs:
                 .peek(Node::peek),
 
                 (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+                NOTHING_OR_PGJDBC_ZERO_COUNT,
+                NOTHING_OR_PGJDBC_ZERO_COUNT,
+                NOTHING_OR_PGJDBC_ZERO_COUNT,
                 (o,p,q) -> null == o
               );
 
@@ -598,6 +605,8 @@ jobs:
               .peek(Node::peek),
 
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
               (o,p,q) -> null == o
             );
           }
@@ -633,6 +642,7 @@ jobs:
               .peek(Node::peek),
 
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
               (o,p,q) -> null == o
             );
 
@@ -647,6 +657,7 @@ jobs:
                 .peek(Node::peek),
 
                 (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+                NOTHING_OR_PGJDBC_ZERO_COUNT,
                 (o,p,q) -> null == o
               );
             }
@@ -672,6 +683,7 @@ jobs:
               .peek(Node::peek),
 
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
               (o,p,q) -> null == o
             );
 
@@ -687,6 +699,8 @@ jobs:
               .peek(Node::peek),
 
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
               (o,p,q) -> null == o
             );
           }
diff --git a/appveyor.yml b/appveyor.yml
index a0e534ee2..ed964f202 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -108,6 +108,8 @@ test_script:
       import static org.postgresql.pljava.packaging.Node.q;
       import static org.postgresql.pljava.packaging.Node.stateMachine;
       import static org.postgresql.pljava.packaging.Node.isVoidResultSet;
+      import static
+        org.postgresql.pljava.packaging.Node.NOTHING_OR_PGJDBC_ZERO_COUNT;
       /*
        * Imports that will be needed to serve a jar file over http
        * when the time comes for testing that.
@@ -221,7 +223,9 @@ test_script:
             // state 1: consume any diagnostics, or show same item to state 2
             (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
 
-            // state 2: must be end of input
+            NOTHING_OR_PGJDBC_ZERO_COUNT, // state 2
+
+            // state 3: must be end of input
             (o,p,q) -> null == o
           );
         }
@@ -448,6 +452,9 @@ test_script:
               .peek(Node::peek),
 
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
               (o,p,q) -> null == o
             );
 
@@ -480,6 +487,8 @@ test_script:
             .peek(Node::peek),
 
             (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+            NOTHING_OR_PGJDBC_ZERO_COUNT,
+            NOTHING_OR_PGJDBC_ZERO_COUNT,
             (o,p,q) -> null == o
           );
         }
@@ -515,6 +524,7 @@ test_script:
             .peek(Node::peek),
 
             (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+            NOTHING_OR_PGJDBC_ZERO_COUNT,
             (o,p,q) -> null == o
           );
 
@@ -529,6 +539,7 @@ test_script:
               .peek(Node::peek),
 
               (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+              NOTHING_OR_PGJDBC_ZERO_COUNT,
               (o,p,q) -> null == o
             );
           }
@@ -554,6 +565,7 @@ test_script:
             .peek(Node::peek),
 
             (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+            NOTHING_OR_PGJDBC_ZERO_COUNT,
             (o,p,q) -> null == o
           );
 
@@ -569,6 +581,8 @@ test_script:
             .peek(Node::peek),
 
             (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+            NOTHING_OR_PGJDBC_ZERO_COUNT,
+            NOTHING_OR_PGJDBC_ZERO_COUNT,
             (o,p,q) -> null == o
           );
         }
diff --git a/pljava-api/src/main/java/org/postgresql/pljava/Adjusting.java b/pljava-api/src/main/java/org/postgresql/pljava/Adjusting.java
index 9a2d379b7..3c8ce6398 100644
--- a/pljava-api/src/main/java/org/postgresql/pljava/Adjusting.java
+++ b/pljava-api/src/main/java/org/postgresql/pljava/Adjusting.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2019-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -14,6 +14,9 @@
 import java.io.Reader;
 import java.sql.SQLException;
 import java.sql.SQLXML;
+import java.util.List;
+import static java.util.Objects.requireNonNull;
+import java.util.function.Consumer;
 import javax.xml.stream.XMLInputFactory; // for javadoc
 import javax.xml.stream.XMLResolver; // for javadoc
 import javax.xml.stream.XMLStreamReader;
@@ -126,16 +129,139 @@ public static final class XML
 	{
 		private XML() { } // no instances
 
+		/**
+		 * Attempts a given action (typically to set something) using a given
+		 * value, trying one or more supplied keys in order until the action
+		 * succeeds with no exception.
+		 *<p>
+		 * This logic is common to the
+		 * {@link Parsing#setFirstSupportedFeature setFirstSupportedFeature}
+		 * and
+		 * {@link Parsing#setFirstSupportedProperty setFirstSupportedProperty}
+		 * methods, and is exposed here because it may be useful for other
+		 * tasks in Java's XML APIs, such as configuring {@code Transformer}s.
+		 *<p>
+		 * If any attempt succeeds, null is returned. If no attempt
+		 * succeeds, the first exception caught is returned, with any
+		 * exceptions from the subsequent attempts retrievable from it with
+		 * {@link Exception#getSuppressed getSuppressed}. The return is
+		 * immediate, without any remaining names being tried, if an exception
+		 * is caught that is not assignable to a class in the
+		 * <var>expected</var> list. Such an exception will be passed to the
+		 * <var>onUnexpected</var> handler if that is non-null; otherwise,
+		 * it will be returned (or added to the suppressed list of the
+		 * exception to be returned) just as expected exceptions are.
+		 * @param setter typically a method reference for a method that
+		 * takes a string key and some value.
+		 * @param value the value to pass to the setter
+		 * @param expected a list of exception classes that can be foreseen
+		 * to indicate that a key was not recognized, and the operation
+		 * should be retried with the next possible key.
+		 * @param onUnexpected invoked, if non-null, on an {@code Exception}
+		 * that is caught and matches nothing in the expected list, instead
+		 * of returning it. If this parameter is null, such an exception is
+		 * returned (or added to the suppressed list of the exception to be
+		 * returned), just as for expected exceptions, but the return is
+		 * immediate, without trying remaining names, if any.
+		 * @param names one or more String keys to be tried in order until
+		 * the action succeeds.
+		 * @return null if any attempt succeeded, otherwise an exception,
+		 * which may have further exceptions in its suppressed list.
+		 */
+		public static <T, V extends T> Exception setFirstSupported(
+			SetMethod<? super T> setter, V value,
+			List<Class<? extends Exception>> expected,
+			Consumer<? super Exception> onUnexpected, String... names)
+		{
+			requireNonNull(expected);
+			Exception caught = null;
+			for ( String name : names )
+			{
+				try
+				{
+					setter.set(name, value);
+					return null;
+				}
+				catch ( Exception e )
+				{
+					boolean benign =
+						expected.stream().anyMatch(c -> c.isInstance(e));
+
+					if ( benign  ||  null == onUnexpected )
+					{
+						if ( null == caught )
+							caught = e;
+						else
+							caught.addSuppressed(e);
+					}
+					else
+						onUnexpected.accept(e);
+
+					if ( ! benign )
+						break;
+				}
+			}
+			return caught;
+		}
+
+		/**
+		 * A functional interface fitting various {@code setFeature} or
+		 * {@code setProperty} methods in Java XML APIs.
+		 *<p>
+		 * The XML APIs have a number of methods on various interfaces that can
+		 * be used to set some property or feature, and can generally be
+		 * assigned to this functional interface by bound method reference, and
+		 * used with {@link #setFirstSupported setFirstSupported}.
+		 */
+		@FunctionalInterface
+		public interface SetMethod<T>
+		{
+			void set(String key, T value) throws Exception;
+		}
+
 		/**
 		 * Interface with methods to adjust the restrictions on XML parsing
 		 * that are commonly considered when XML content might be from untrusted
 		 * sources.
 		 *<p>
-		 * The adjusting methods are best-effort and do not provide an
-		 * indication of whether the requested adjustment was made. Not all of
+		 * The adjusting methods are best-effort; not all of
 		 * the adjustments are available for all flavors of {@code Source} or
 		 * {@code Result} or for all parser implementations or versions the Java
-		 * runtime may supply.
+		 * runtime may supply. Cases where a requested adjustment has not been
+		 * made are handled as follows:
+		 *<p>
+		 * Any sequence of adjustment calls will ultimately be followed by a
+		 * {@code get}. During the sequence of adjustments, exceptions caught
+		 * are added to a signaling list or to a quiet list, where "added to"
+		 * means that if either list has a first exception, any caught later are
+		 * attached to that exception with
+		 * {@link Exception#addSuppressed addSuppressed}.
+		 *<p>
+		 * For each adjustment (and depending on the type of underlying
+		 * {@code Source} or {@code Result}), one or more exception types will
+		 * be 'expected' as indications that an identifying key or value for
+		 * that adjustment was not recognized. This implementation may continue
+		 * trying to apply the adjustment, using other keys that have at times
+		 * been used to identify it. Expected exceptions caught during these
+		 * attempts form a temporary list (a first exception and those attached
+		 * to it by {@code addSuppressed}). Once any such attempt succeeds, the
+		 * adjustment is considered made, and any temporary expected exceptions
+		 * list from the adjustment is discarded. If no attempt succeeded, the
+		 * temporary list is retained, by adding its head exception to the quiet
+		 * list.
+		 *<p>
+		 * Any exceptions caught that are not instances of any of the 'expected'
+		 * types are added to the signaling list.
+		 *<p>
+		 * When {@code get} is called, the head exception on the signaling list,
+		 * if any, is thrown. Otherwise, the head exception on the quiet list,
+		 * if any, is logged at {@code WARNING} level.
+		 *<p>
+		 * During a chain of adjustments, {@link #lax lax()} can be called to
+		 * tailor the handling of the quiet list. A {@code lax()} call applies
+		 * to whatever exceptions have been added to the quiet list up to that
+		 * point. To discard them, call {@code lax(true)}; to move them to the
+		 * signaling list, call {@code lax(false)}.
 		 */
 		public interface Parsing<T extends Parsing<T>>
 		{
@@ -173,14 +299,14 @@ public interface Parsing<T extends Parsing<T>>
 
 			/**
 			 * For a feature that may have been identified by more than one URI
-			 * in different parsers or versions, try passing the supplied
+			 * in different parsers or versions, tries passing the supplied
 			 * <em>value</em> with each URI from <em>names</em> in order until
 			 * one is not rejected by the underlying parser.
 			 */
 			T setFirstSupportedFeature(boolean value, String... names);
 
 			/**
-			 * Make a best effort to apply the recommended, restrictive
+			 * Makes a best effort to apply the recommended, restrictive
 			 * defaults from the OWASP cheat sheet, to the extent they are
 			 * supported by the underlying parser, runtime, and version.
 			 *<p>
@@ -196,7 +322,7 @@ public interface Parsing<T extends Parsing<T>>
 			/**
 			 * For a parser property (in DOM parlance, attribute) that may have
 			 * been identified by more than one URI in different parsers or
-			 * versions, try passing the supplied <em>value</em> with each URI
+			 * versions, tries passing the supplied <em>value</em> with each URI
 			 * from <em>names</em> in order until one is not rejected by the
 			 * underlying parser.
 			 *<p>
@@ -278,7 +404,7 @@ public interface Parsing<T extends Parsing<T>>
 			T accessExternalSchema(String protocols);
 
 			/**
-			 * Set an {@link EntityResolver} of the type used by SAX and DOM
+			 * Sets an {@link EntityResolver} of the type used by SAX and DOM
 			 * <em>(optional operation)</em>.
 			 *<p>
 			 * This method only succeeds for a {@code SAXSource} or
@@ -297,7 +423,7 @@ public interface Parsing<T extends Parsing<T>>
 			T entityResolver(EntityResolver resolver);
 
 			/**
-			 * Set a {@link Schema} to be applied during SAX or DOM parsing
+			 * Sets a {@link Schema} to be applied during SAX or DOM parsing
 			 *<em>(optional operation)</em>.
 			 *<p>
 			 * This method only succeeds for a {@code SAXSource} or
@@ -316,6 +442,31 @@ public interface Parsing<T extends Parsing<T>>
 			 * already.
 			 */
 			T schema(Schema schema);
+
+			/**
+			 * Tailors the treatment of 'quiet' exceptions during a chain of
+			 * best-effort adjustments.
+			 *<p>
+			 * See {@link Parsing the class description} for an explanation of
+			 * the signaling and quiet lists.
+			 *<p>
+			 * This method applies to whatever exceptions may have been added to
+			 * the quiet list by best-effort adjustments made up to that point.
+			 * They can be moved to the signaling list with {@code lax(false)},
+			 * or simply discarded with {@code lax(true)}. In either case, the
+			 * quiet list is left empty when {@code lax} returns.
+			 *<p>
+			 * At the time a {@code get} method is later called, any exception
+			 * at the head of the signaling list will be thrown (possibly
+			 * wrapped in an exception permitted by {@code get}'s {@code throws}
+			 * clause), with any later exceptions on that list retrievable from
+			 * the head exception with
+			 * {@link Exception#getSuppressed getSuppressed}. Otherwise, any
+			 * exception at the head of the quiet list (again with any later
+			 * ones attached as its suppressed list) will be logged at
+			 * {@code WARNING} level.
+			 */
+			T lax(boolean discard);
 		}
 
 		/**
@@ -347,12 +498,17 @@ public interface Source<T extends javax.xml.transform.Source>
 		extends Parsing<Source<T>>, javax.xml.transform.Source
 		{
 			/**
-			 * Return an object of the expected {@code Source} subtype
+			 * Returns an object of the expected {@code Source} subtype
 			 * reflecting any adjustments made with the other methods.
+			 *<p>
+			 * Refer to {@link Parsing the {@code Parsing} class description}
+			 * and the {@link Parsing#lax lax()} method for how any exceptions
+			 * caught while applying best-effort adjustments are handled.
 			 * @return an implementing object of the expected Source subtype
 			 * @throws SQLException for any reason that {@code getSource} might
 			 * have thrown when supplying the corresponding non-Adjusting
-			 * subtype of Source.
+			 * subtype of Source, or for reasons saved while applying
+			 * adjustments.
 			 */
 			T get() throws SQLException;
 		}
@@ -392,12 +548,16 @@ public interface Result<T extends javax.xml.transform.Result>
 		extends Parsing<Result<T>>, javax.xml.transform.Result
 		{
 			/**
-			 * Return an object of the expected {@code Result} subtype
+			 * Returns an object of the expected {@code Result} subtype
 			 * reflecting any adjustments made with the other methods.
+			 * Refer to {@link Parsing the {@code Parsing} class description}
+			 * and the {@link Parsing#lax lax()} method for how any exceptions
+			 * caught while applying best-effort adjustments are handled.
 			 * @return an implementing object of the expected Result subtype
 			 * @throws SQLException for any reason that {@code getResult} might
 			 * have thrown when supplying the corresponding non-Adjusting
-			 * subtype of Result.
+			 * subtype of Result, or for reasons saved while applying
+			 * adjustments.
 			 */
 			T get() throws SQLException;
 		}
@@ -428,7 +588,7 @@ public interface Result<T extends javax.xml.transform.Result>
 		public interface SourceResult extends Result<SourceResult>
 		{
 			/**
-			 * Supply the {@code Source} instance that is the source of the
+			 * Supplies the {@code Source} instance that is the source of the
 			 * content.
 			 *<p>
 			 * This method must be called before any of the inherited adjustment
@@ -484,7 +644,8 @@ SourceResult set(javax.xml.transform.stax.StAXSource source)
 			throws SQLException;
 
 			/**
-			 * Provide the content to be copied in the form of a {@code String}.
+			 * Provides the content to be copied in the form of a
+			 * {@code String}.
 			 *<p>
 			 * An exception from the pattern of {@code Source}-typed arguments,
 			 * this method simplifies retrofitting adjustments into code that
@@ -507,11 +668,14 @@ SourceResult set(javax.xml.transform.dom.DOMSource source)
 			throws SQLException;
 
 			/**
-			 * Return the result {@code SQLXML} instance ready for handing off
+			 * Returns the result {@code SQLXML} instance ready for handing off
 			 * to PostgreSQL.
 			 *<p>
-			 * This method must be called after any of the inherited adjustment
-			 * methods.
+			 * The handling/logging of exceptions normally handled in a
+			 * {@code get} method happens here for a {@code SourceResult}.
+			 *<p>
+			 * Any necessary calls of the inherited adjustment methods must be
+			 * made before this method is called.
 			 */
 			SQLXML getSQLXML() throws SQLException;
 		}
diff --git a/pljava-api/src/main/java/org/postgresql/pljava/annotation/package-info.java b/pljava-api/src/main/java/org/postgresql/pljava/annotation/package-info.java
index de7309e5b..ca5af21cf 100644
--- a/pljava-api/src/main/java/org/postgresql/pljava/annotation/package-info.java
+++ b/pljava-api/src/main/java/org/postgresql/pljava/annotation/package-info.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2016 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2015-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -33,11 +33,10 @@
  * <p>
  * Automatic descriptor generation requires attention to a few things.
  * <ul>
- * <li>A Java 6 or later Java compiler is required, and at least the
- * <code>pljava-api</code> jar must be on its class path. (The full
- * <code>pljava.jar</code> would also work, but only <code>pljava-api</code>
- * is required.) The jar must be on the class path in any case in order to
- * compile PL/Java code.
+ * <li>The {@code pljava-api} jar must be on the Java compiler's class path.
+ * (All but the simplest PL/Java functions probably refer to some class in
+ * PL/Java's API anyway, in which case the jar would already have to be on
+ * the class path.)
  * <li>When recompiling after changing only a few sources, it is possible the
  * Java compiler will only process a subset of the source files containing
  * annotations. If so, it may generate an incomplete deployment descriptor,
diff --git a/pljava-api/src/main/java/org/postgresql/pljava/annotation/processing/DDRProcessor.java b/pljava-api/src/main/java/org/postgresql/pljava/annotation/processing/DDRProcessor.java
index 56eda5fc0..ccd2a8a7f 100644
--- a/pljava-api/src/main/java/org/postgresql/pljava/annotation/processing/DDRProcessor.java
+++ b/pljava-api/src/main/java/org/postgresql/pljava/annotation/processing/DDRProcessor.java
@@ -173,7 +173,7 @@ public SourceVersion getSupportedSourceVersion()
 		 * Update latest_tested to be the latest Java release on which this
 		 * annotation processor has been tested without problems.
 		 */
-		int latest_tested = 20;
+		int latest_tested = 21;
 		int ordinal_9 = SourceVersion.RELEASE_9.ordinal();
 		int ordinal_latest = latest_tested - 9 + ordinal_9;
 
diff --git a/pljava-api/src/main/java/org/postgresql/pljava/sqlgen/Lexicals.java b/pljava-api/src/main/java/org/postgresql/pljava/sqlgen/Lexicals.java
index 85bdc66bc..1b6e014a0 100644
--- a/pljava-api/src/main/java/org/postgresql/pljava/sqlgen/Lexicals.java
+++ b/pljava-api/src/main/java/org/postgresql/pljava/sqlgen/Lexicals.java
@@ -279,7 +279,7 @@ private Lexicals() { } // do not instantiate
 	 * engine, letting it handle the details.
 	 */
 	public static final Pattern NEWLINE = Pattern.compile(
-		"(?ms:$(?:(?<!^).|(?<=\\G).){1,2}+)"
+		"(?ms:$.{1,2}?(?:^|\\z))" // fewest of 1,2 chars between $ and ^ (or \z)
 	);
 
 	/** White space <em>except</em> newline, for any Java-recognized newline.
diff --git a/pljava-api/src/test/java/LexicalsTest.java b/pljava-api/src/test/java/LexicalsTest.java
index 174258115..89b94d07f 100644
--- a/pljava-api/src/test/java/LexicalsTest.java
+++ b/pljava-api/src/test/java/LexicalsTest.java
@@ -29,6 +29,8 @@
 
 import static
 	org.postgresql.pljava.sqlgen.Lexicals.ISO_AND_PG_IDENTIFIER_CAPTURING;
+import static
+	org.postgresql.pljava.sqlgen.Lexicals.NEWLINE;
 import static
 	org.postgresql.pljava.sqlgen.Lexicals.SEPARATOR;
 import static
@@ -45,6 +47,22 @@ public class LexicalsTest extends TestCase
 {
 	public LexicalsTest(String name) { super(name); }
 
+	public void testNewline() throws Exception
+	{
+		Matcher m = NEWLINE.matcher("abcd\nefgh");
+		m.region(4, 9);
+		assertTrue("newline 0", m.lookingAt());
+		assertTrue("newline 1", m.lookingAt());
+
+		m.reset("abcd\r\nefgh").region(4, 10);
+		assertTrue("newline 2", m.lookingAt());
+		assertEquals("\r\n", m.group());
+
+		m.reset("abcd\n\refgh").region(4, 10);
+		assertTrue("newline 3", m.lookingAt());
+		assertEquals("\n", m.group());
+	}
+
 	public void testSeparator() throws Exception
 	{
 		Pattern allTheRest = Pattern.compile(".*", Pattern.DOTALL);
diff --git a/pljava-examples/pom.xml b/pljava-examples/pom.xml
index f371bedf3..00079e9f2 100644
--- a/pljava-examples/pom.xml
+++ b/pljava-examples/pom.xml
@@ -230,11 +230,13 @@ function executeReport(report, locale)
 		 * A special file manager that will rewrite the RELDOTS seen in
 		 * -linkoffline above. The options a file manager recognizes must be the
 		 * first ones in args; handleFirstOptions below returns at the first one
-		 * the file manager doesn't know what to do with.
+		 * the file manager doesn't know what to do with. Java 19 seems to have
+		 * learned to pass the args to the file manager without the fuss here.
 		 */
 		var rmgr = new org.postgresql.pljava.pgxs.RelativizingFileManager(
 			smgr, Charset.forName(report.outputEncoding));
-		rmgr.handleFirstOptions(args);
+		if ( 0 > v.compareTo(java.lang.Runtime.Version.parse("19-ea")) )
+			rmgr.handleFirstOptions(args);
 
 		var task = tool.getTask(null, rmgr, diagListener, null, args, null);
 		if (task.call())
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/ConditionalDDR.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/ConditionalDDR.java
index 0140f4372..21375c909 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/ConditionalDDR.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/ConditionalDDR.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2015-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -64,7 +64,7 @@
  * local, so it is reverted when the transaction completes.
  * <p>
  * In addition to the goodness-of-life examples, this file also generates
- * several statements setting PostgreSQL-version-based implementor tags that
+ * one or more statements setting PostgreSQL-version-based implementor tags that
  * are relied on by various other examples in this directory.
  */
 @SQLAction(provides={"LifeIsGood","LifeIsNotGood"}, install=
@@ -78,51 +78,12 @@
 )
 
 @SQLAction(implementor="LifeIsGood", install=
-	"SELECT javatest.logmessage('INFO', 'Looking good!')"
+	"SELECT javatest.logmessage('INFO', 'ConditionalDDR looking good!')"
 )
 
 @SQLAction(implementor="LifeIsNotGood", install=
-	"SELECT javatest.logmessage('WARNING', 'This should not be executed')"
-)
-
-@SQLAction(provides="postgresql_ge_80300", install=
-	"SELECT CASE WHEN" +
-	" 80300 <= CAST(current_setting('server_version_num') AS integer)" +
-	" THEN set_config('pljava.implementors', 'postgresql_ge_80300,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
-)
-
-@SQLAction(provides="postgresql_ge_80400", install=
-	"SELECT CASE WHEN" +
-	" 80400 <= CAST(current_setting('server_version_num') AS integer)" +
-	" THEN set_config('pljava.implementors', 'postgresql_ge_80400,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
-)
-
-@SQLAction(provides="postgresql_ge_90000", install=
-	"SELECT CASE WHEN" +
-	" 90000 <= CAST(current_setting('server_version_num') AS integer)" +
-	" THEN set_config('pljava.implementors', 'postgresql_ge_90000,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
-)
-
-@SQLAction(provides="postgresql_ge_90100", install=
-	"SELECT CASE WHEN" +
-	" 90100 <= CAST(current_setting('server_version_num') AS integer)" +
-	" THEN set_config('pljava.implementors', 'postgresql_ge_90100,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
-)
-
-@SQLAction(provides="postgresql_ge_90300", install=
-	"SELECT CASE WHEN" +
-	" 90300 <= CAST(current_setting('server_version_num') AS integer)" +
-	" THEN set_config('pljava.implementors', 'postgresql_ge_90300,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
+	"SELECT javatest.logmessage('WARNING', " +
+	" 'ConditionalDDR: This should not be executed')"
 )
 
 @SQLAction(provides="postgresql_ge_100000", install=
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Enumeration.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Enumeration.java
index 2fcee7df1..359bb2871 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Enumeration.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Enumeration.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2015-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -21,16 +21,12 @@
 /**
  * Confirms the mapping of PG enum and Java String, and arrays of each, as
  * parameter and return types.
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example. PostgreSQL before 8.3
- * did not have enum types.
  */
-@SQLAction(provides="mood type", implementor="postgresql_ge_80300",
+@SQLAction(provides="mood type",
 	install="CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy')",
 	remove="DROP TYPE mood"
 )
-@SQLAction(implementor="postgresql_ge_80300",
+@SQLAction(
 	requires={"textToMood", "moodToText", "textsToMoods", "moodsToTexts"},
 	install={
 		"SELECT textToMood('happy')",
@@ -41,26 +37,22 @@
 )
 public class Enumeration
 {
-	@Function(requires="mood type", provides="textToMood", type="mood",
-			  implementor="postgresql_ge_80300")
+	@Function(requires="mood type", provides="textToMood", type="mood")
 	public static String textToMood(String s)
 	{
 		return s;
 	}
-	@Function(requires="mood type", provides="moodToText",
-			  implementor="postgresql_ge_80300")
+	@Function(requires="mood type", provides="moodToText")
 	public static String moodToText(@SQLType("mood")String s)
 	{
 		return s;
 	}
-	@Function(requires="mood type", provides="textsToMoods", type="mood",
-			  implementor="postgresql_ge_80300")
+	@Function(requires="mood type", provides="textsToMoods", type="mood")
 	public static Iterator<String> textsToMoods(String[] ss)
 	{
 		return Arrays.asList(ss).iterator();
 	}
-	@Function(requires="mood type", provides="moodsToTexts",
-			  implementor="postgresql_ge_80300")
+	@Function(requires="mood type", provides="moodsToTexts")
 	public static Iterator<String> moodsToTexts(@SQLType("mood[]")String[] ss)
 	{
 		return Arrays.asList(ss).iterator();
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/JDBC42_21.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/JDBC42_21.java
index 1b0d35e28..ff2c23116 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/JDBC42_21.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/JDBC42_21.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2022 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -14,20 +14,15 @@
 import org.postgresql.pljava.annotation.Function;
 import org.postgresql.pljava.annotation.SQLAction;
 
-import org.postgresql.pljava.example.annotation.ConditionalDDR; // for javadoc
-
 /**
  * Exercise new mappings between date/time types and java.time classes
  * (JDBC 4.2 change 21).
  *<p>
  * Defines a method {@link #javaSpecificationGE javaSpecificationGE} that may be
  * of use for other examples.
- *<p>
- * Relies on PostgreSQL-version-specific implementor tags set up in the
- * {@link ConditionalDDR} example.
  */
 @SQLAction(
-	implementor="postgresql_ge_90300",requires="TypeRoundTripper.roundTrip",
+	requires="TypeRoundTripper.roundTrip",
 	install={
 	" SELECT" +
 	"  CASE WHEN every(orig = roundtripped)" +
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PGF1010962.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PGF1010962.java
index 2b06f481e..747f2ef6d 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PGF1010962.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PGF1010962.java
@@ -10,12 +10,8 @@
 /**
  * A gnarly test of TupleDesc reference management, crafted by Johann Oskarsson
  * for bug report 1010962 on pgFoundry.
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example. Before PostgreSQL 8.4,
- * there is no array of {@code RECORD}, which this test requires.
  */
-@SQLAction(requires="1010962 func", implementor="postgresql_ge_80400",
+@SQLAction(requires="1010962 func",
 	install={
 		"CREATE TYPE javatest.B1010962 AS ( b1_val float8, b2_val int)",
 
@@ -51,8 +47,7 @@ public class PGF1010962
 	 * @param receiver Looks polymorphic, but expects an array of A1010962
 	 * @return 0
 	 */
-	@Function(schema="javatest", provides="1010962 func",
-				implementor="postgresql_ge_80400")
+	@Function(schema="javatest", provides="1010962 func")
 	public static int complexParam( ResultSet receiver[] )
 	throws SQLException
 	{
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PassXML.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PassXML.java
index e735376c2..37ad6eb8e 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PassXML.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PassXML.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -36,6 +36,7 @@
 
 import java.io.IOException;
 
+import java.util.List;
 import java.util.Map;
 import java.util.HashMap;
 
@@ -65,6 +66,7 @@
 import javax.xml.validation.SchemaFactory;
 
 import org.postgresql.pljava.Adjusting;
+import static org.postgresql.pljava.Adjusting.XML.setFirstSupported;
 import org.postgresql.pljava.annotation.Function;
 import org.postgresql.pljava.annotation.MappedUDT;
 import org.postgresql.pljava.annotation.SQLAction;
@@ -112,16 +114,7 @@
 	"END"
 )
 
-@SQLAction(implementor="postgresql_ge_80400",
-	provides="postgresql_xml_ge84",
-	install=
-	"SELECT CASE (SELECT 1 FROM pg_type WHERE typname = 'xml') WHEN 1" +
-	" THEN set_config('pljava.implementors', 'postgresql_xml_ge84,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
-)
-
-@SQLAction(implementor="postgresql_xml_ge84", requires="echoXMLParameter",
+@SQLAction(implementor="postgresql_xml", requires="echoXMLParameter",
 	install=
 	"WITH" +
 	" s(how) AS (SELECT generate_series(1, 7))," +
@@ -146,7 +139,7 @@
 	" r"
 )
 
-@SQLAction(implementor="postgresql_xml_ge84", requires="proxiedXMLEcho",
+@SQLAction(implementor="postgresql_xml", requires="proxiedXMLEcho",
 	install=
 	"WITH" +
 	" s(how) AS (SELECT unnest('{1,2,4,5,6,7}'::int[]))," +
@@ -170,7 +163,7 @@
 	" r"
 )
 
-@SQLAction(implementor="postgresql_xml_ge84", requires="lowLevelXMLEcho",
+@SQLAction(implementor="postgresql_xml", requires="lowLevelXMLEcho",
 	install={
 	"SELECT" +
 	" preparexmlschema('schematest', $$" +
@@ -518,33 +511,51 @@ private static void prepareXMLTransform(String name, SQLXML source, int how,
 			builtin
 			? TransformerFactory.newDefaultInstance()
 			: TransformerFactory.newInstance();
-		String exf =
-		  "http://www.oracle.com/xml/jaxp/properties/enableExtensionFunctions";
-		String ecl = "jdk.xml.transform.extensionClassLoader";
+
+		String legacy_pfx = "http://www.oracle.com/xml/jaxp/properties/";
+		String java17_pfx = "jdk.xml.";
+		String exf_sfx = "enableExtensionFunctions";
+
+		String ecl_legacy = "jdk.xml.transform.extensionClassLoader";
+		String ecl_java17 = "jdk.xml.extensionClassLoader";
+
 		Source src = sxToSource(source, how, adjust);
+
 		try
 		{
-			try
-			{
-				tf.setFeature(exf, enableExtensionFunctions);
-			}
-			catch ( TransformerConfigurationException e )
+			Exception e;
+
+			e = setFirstSupported(tf::setFeature, enableExtensionFunctions,
+				List.of(TransformerConfigurationException.class), null,
+				java17_pfx + exf_sfx, legacy_pfx + exf_sfx);
+
+			if ( null != e )
 			{
-				logMessage("WARNING",
-					"non-builtin transformer: ignoring " + e.getMessage());
+				if ( builtin )
+					throw new SQLException(
+						"Configuring XML transformation: " + e.getMessage(), e);
+				else
+					logMessage("WARNING",
+						"non-builtin transformer: ignoring " + e.getMessage());
 			}
 
 			if ( withJava )
 			{
-				try
-				{
-					tf.setAttribute(ecl,
-						Thread.currentThread().getContextClassLoader());
-				}
-				catch ( IllegalArgumentException e )
+				e = setFirstSupported(tf::setAttribute,
+					Thread.currentThread().getContextClassLoader(),
+					List.of(IllegalArgumentException.class), null,
+					ecl_java17, ecl_legacy);
+
+				if ( null != e )
 				{
-					logMessage("WARNING",
-					"non-builtin transformer: ignoring " + e.getMessage());
+					if ( builtin )
+						throw new SQLException(
+							"Configuring XML transformation: " + 
+								e.getMessage(), e);
+					else
+						logMessage("WARNING",
+							"non-builtin transformer: ignoring " + 
+								e.getMessage());
 				}
 			}
 
@@ -702,7 +713,7 @@ private static SQLXML echoSQLXML(SQLXML sx, int howin, int howout)
 	 * still be exercised by calling this method, explicitly passing
 	 * {@code adjust => NULL}.
 	 */
-	@Function(schema="javatest", implementor="postgresql_xml_ge84",
+	@Function(schema="javatest", implementor="postgresql_xml",
 		provides="lowLevelXMLEcho")
 	public static SQLXML lowLevelXMLEcho(
 		SQLXML sx, int how, @SQLType(defaultValue={}) ResultSet adjust)
@@ -789,7 +800,9 @@ T applyAdjustments(ResultSet adjust, T axp)
 		for ( int i = 1; i <= n; ++i )
 		{
 			String k = rsmd.getColumnLabel(i);
-			if ( "allowDTD".equalsIgnoreCase(k) )
+			if ( "lax".equalsIgnoreCase(k) )
+				axp.lax(adjust.getBoolean(i));
+			else if ( "allowDTD".equalsIgnoreCase(k) )
 				axp.allowDTD(adjust.getBoolean(i));
 			else if ( "externalGeneralEntities".equalsIgnoreCase(k) )
 				axp.externalGeneralEntities(adjust.getBoolean(i));
@@ -1046,12 +1059,9 @@ public static SQLXML mockedXMLEcho(String chars)
 
 	/**
 	 * Text-typed variant of lowLevelXMLEcho (does not require XML type).
-	 *<p>
-	 * It does declare a parameter default, limiting it to PostgreSQL 8.4 or
-	 * later.
 	 */
 	@Function(schema="javatest", name="lowLevelXMLEcho",
-		type="text", implementor="postgresql_ge_80400")
+		type="text")
 	public static SQLXML lowLevelXMLEcho_(@SQLType("text") SQLXML sx, int how,
 		@SQLType(defaultValue={}) ResultSet adjust)
 	throws SQLException
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PreJSR310.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PreJSR310.java
index e430e25d1..726d46a5d 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PreJSR310.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PreJSR310.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -29,9 +29,6 @@
  * Some tests of pre-JSR 310 date/time/timestamp conversions.
  *<p>
  * For now, just {@code java.sql.Date}, thanks to issue #199.
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example.
  */
 @SQLAction(provides="language java_tzset", install={
 	"SELECT sqlj.alias_java_language('java_tzset', true)"
@@ -39,7 +36,7 @@
 	"DROP LANGUAGE java_tzset"
 })
 
-@SQLAction(implementor="postgresql_ge_90300", // needs LATERAL
+@SQLAction(
 	requires="issue199", install={
 	"SELECT javatest.issue199()"
 })
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/RecordParameterDefaults.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/RecordParameterDefaults.java
index 09d3dbbe8..291eb990b 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/RecordParameterDefaults.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/RecordParameterDefaults.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -19,7 +19,6 @@
 
 import org.postgresql.pljava.ResultSetProvider;
 import org.postgresql.pljava.annotation.Function;
-import org.postgresql.pljava.annotation.SQLAction;
 import org.postgresql.pljava.annotation.SQLType;
 
 /**
@@ -28,21 +27,7 @@
  * function.
  *<p>
  * Also tests the proper DDR generation of defaults for such parameters.
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example.
  */
-@SQLAction(
-	provides = "paramtypeinfo type", // created in Triggers.java
-	install = {
-		"CREATE TYPE javatest.paramtypeinfo AS (" +
-		" name text, pgtypename text, javaclass text, tostring text" +
-		")"
-	},
-	remove = {
-		"DROP TYPE javatest.paramtypeinfo"
-	}
-)
 public class RecordParameterDefaults implements ResultSetProvider
 {
 	/**
@@ -62,11 +47,11 @@ public class RecordParameterDefaults implements ResultSetProvider
 	 *</pre>
 	 */
 	@Function(
-		requires = "paramtypeinfo type",
 		schema = "javatest",
-		implementor = "postgresql_ge_80400", // supports function param DEFAULTs
-		type = "javatest.paramtypeinfo"
-		)
+		out = {
+			"name text", "pgtypename text", "javaclass text", "tostring text"
+		}
+	)
 	public static ResultSetProvider paramDefaultsRecord(
 		@SQLType(defaultValue={})ResultSet params)
 	throws SQLException
@@ -87,7 +72,6 @@ public static ResultSetProvider paramDefaultsRecord(
 	 */
 	@Function(
 		requires = "foobar tables", // created in Triggers.java
-		implementor = "postgresql_ge_80400", // supports function param DEFAULTs
 		schema = "javatest"
 		)
 	public static String paramDefaultsNamedRow(
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/SetOfRecordTest.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/SetOfRecordTest.java
index 13fce44d4..49abf1382 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/SetOfRecordTest.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/SetOfRecordTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -26,12 +26,8 @@
  * Example implementing the {@code ResultSetHandle} interface, to return
  * the {@link ResultSet} from any SQL {@code SELECT} query passed as a string
  * to the {@link #executeSelect executeSelect} function.
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example. Before PostgreSQL 8.4,
- * there was no {@code =} or {@code DISTINCT FROM} operator between row types.
  */
-@SQLAction(requires="selecttorecords fn", implementor="postgresql_ge_80400",
+@SQLAction(requires="selecttorecords fn",
 install=
 " SELECT " +
 "  CASE WHEN r IS DISTINCT FROM ROW('Foo'::varchar, 1::integer, 1.5::float, " +
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Triggers.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Triggers.java
index 804ef9d83..bfdbf8c0f 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Triggers.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/Triggers.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -38,8 +38,8 @@
  * also create a function and trigger that uses transition tables.
  *<p>
  * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example. Constraint triggers
- * appear in PG 9.1, transition tables in PG 10.
+ * version, set up in the {@link ConditionalDDR} example. Transition tables
+ * appear in PG 10.
  */
 @SQLAction(
 	provides = "foobar tables",
@@ -135,10 +135,8 @@ public static void examineRows(TriggerData td)
 
 	/**
 	 * Throw exception if value to be inserted is 44.
-	 * Constraint triggers first became available in PostgreSQL 9.1.
 	 */
 	@Function(
-		implementor = "postgresql_ge_90100",
 		requires = "foobar tables",
 		provides = "constraint triggers",
 		schema = "javatest",
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/TypeRoundTripper.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/TypeRoundTripper.java
index df613c266..8c3151556 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/TypeRoundTripper.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/TypeRoundTripper.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -36,8 +36,6 @@
 import org.postgresql.pljava.annotation.SQLAction;
 import org.postgresql.pljava.annotation.SQLType;
 
-import org.postgresql.pljava.example.annotation.ConditionalDDR; // for javadoc
-
 /**
  * A class to simplify testing of PL/Java's mappings between PostgreSQL and
  * Java/JDBC types.
@@ -94,11 +92,8 @@
  *  (VALUES (timestamptz '2017-08-21 18:25:29.900005Z')) AS p(orig),
  *  roundtrip(p) AS (roundtripped timestamptz);
  *</pre>
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example.
  */
-@SQLAction(implementor = "postgresql_ge_90300", // funcs see earlier FROM items
+@SQLAction(
 	requires = {"TypeRoundTripper.roundTrip", "point mirror type"},
 	install = {
 	" SELECT" +
@@ -309,8 +304,7 @@ private TypeRoundTripper() { }
 	@Function(
 		schema = "javatest",
 		type = "RECORD",
-		provides = "TypeRoundTripper.roundTrip",
-		implementor = "postgresql_ge_80400" // supports function param DEFAULTs
+		provides = "TypeRoundTripper.roundTrip"
 		)
 	public static boolean roundTrip(
 		ResultSet in, @SQLType(defaultValue="") String classname,
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/UnicodeRoundTripTest.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/UnicodeRoundTripTest.java
index 4f2c0ec47..c317dab25 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/UnicodeRoundTripTest.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/UnicodeRoundTripTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2015-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -35,11 +35,10 @@
  * if {@code matched} is false or the original and returned arrays or strings
  * do not match as seen in SQL.
  * <p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example, and also sets its own.
+ * This example sets an {@code implementor} tag based on a PostgreSQL condition,
+ * as further explained in the {@link ConditionalDDR} example.
  */
-@SQLAction(provides="postgresql_unicodetest",
-	implementor="postgresql_ge_90000", install=
+@SQLAction(provides="postgresql_unicodetest", install=
 	"SELECT CASE" +
 	" WHEN 'UTF8' = current_setting('server_encoding')" +
 	" THEN set_config('pljava.implementors', 'postgresql_unicodetest,' ||" +
@@ -49,50 +48,43 @@
 @SQLAction(requires="unicodetest fn",
 implementor="postgresql_unicodetest",
 install=
-"   with " +
-"    usable_codepoints ( cp ) as ( " +
-"     select generate_series(1,x'd7ff'::int) " +
-"     union all " +
-"     select generate_series(x'e000'::int,x'10ffff'::int) " +
+"   WITH " +
+"    usable_codepoints ( cp ) AS ( " +
+"     SELECT generate_series(1,x'd7ff'::int) " +
+"     UNION ALL " +
+"     SELECT generate_series(x'e000'::int,x'10ffff'::int) " +
 "    ), " +
-"    test_inputs ( groupnum, cparray, s ) as ( " +
-"     select " +
-"       cp / 1024 as groupnum, " +
-"       array_agg(cp order by cp), string_agg(chr(cp), '' order by cp) " +
-"     from usable_codepoints " +
-"     group by groupnum " +
+"    test_inputs ( groupnum, cparray, s ) AS ( " +
+"     SELECT " +
+"       cp / 1024 AS groupnum, " +
+"       array_agg(cp ORDER BY cp), string_agg(chr(cp), '' ORDER BY cp) " +
+"     FROM usable_codepoints " +
+"     GROUP BY groupnum " +
 "    ), " +
-"    test_outputs as ( " +
-"     select groupnum, cparray, s, unicodetest(s, cparray) as roundtrip " +
-"     from test_inputs " +
+"    test_outputs AS ( " +
+"     SELECT groupnum, cparray, s, unicodetest(s, cparray) AS roundtrip " +
+"     FROM test_inputs " +
 "    ), " +
-"    test_failures as ( " +
-"     select * " +
-"     from test_outputs " +
-"     where " +
-"      cparray != (roundtrip).cparray or s != (roundtrip).s " +
-"      or not (roundtrip).matched " +
+"    test_failures AS ( " +
+"     SELECT * " +
+"     FROM test_outputs " +
+"     WHERE " +
+"      cparray != (roundtrip).cparray OR s != (roundtrip).s " +
+"      OR NOT (roundtrip).matched " +
 "    ), " +
-"    test_summary ( n_failing_groups, first_failing_group ) as ( " +
-"     select count(*), min(groupnum) from test_failures " +
+"    test_summary ( n_failing_groups, first_failing_group ) AS ( " +
+"     SELECT count(*), min(groupnum) FROM test_failures " +
 "    ) " +
-"   select " +
-"    case when n_failing_groups > 0 then " +
+"   SELECT " +
+"    CASE WHEN n_failing_groups > 0 THEN " +
 "     javatest.logmessage('WARNING', n_failing_groups || " +
 "      ' 1k codepoint ranges had mismatches, first is block starting 0x' || " +
 "      to_hex(1024 * first_failing_group)) " +
-"    else " +
+"    ELSE " +
 "     javatest.logmessage('INFO', " +
 "        'all Unicode codepoint ranges roundtripped successfully.') " +
-"    end " +
-"    from test_summary"
-)
-@SQLAction(
-	install=
-		"CREATE TYPE unicodetestrow AS " +
-		"(matched boolean, cparray integer[], s text)",
-	remove="DROP TYPE unicodetestrow",
-	provides="unicodetestrow type"
+"    END " +
+"    FROM test_summary"
 )
 public class UnicodeRoundTripTest {
 	/**
@@ -111,8 +103,8 @@ public class UnicodeRoundTripTest {
 	 * @param rs OUT (matched, cparray, s) as described above
 	 * @return true to indicate the OUT tuple is not null
 	 */
-	@Function(type="unicodetestrow",
-		requires="unicodetestrow type", provides="unicodetest fn")
+	@Function(out={"matched boolean", "cparray integer[]", "s text"},
+		provides="unicodetest fn")
 	public static boolean unicodetest(String s, int[] ints, ResultSet rs)
 	throws SQLException {
 		boolean ok = true;
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/VarlenaUDTTest.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/VarlenaUDTTest.java
index ae1be8991..c9982490e 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/VarlenaUDTTest.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/VarlenaUDTTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015- Tada AB and other contributors, as listed below.
+ * Copyright (c) 2015-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -29,14 +29,12 @@
  * characters. That makes it easy to test how big a value gets correctly stored
  * and retrieved. It should be about a GB, but in issue 52 was failing at 32768
  * because of a narrowing assignment in the native code.
- *<p>
- * This example relies on {@code implementor} tags reflecting the PostgreSQL
- * version, set up in the {@link ConditionalDDR} example.
  */
-@SQLAction(requires="varlena UDT", implementor="postgresql_ge_80300", install=
+@SQLAction(requires="varlena UDT", install=
 "  SELECT CASE v::text = v::javatest.VarlenaUDTTest::text " +
-"   WHEN true THEN javatest.logmessage('INFO', 'works for ' || v) " +
-"   ELSE javatest.logmessage('WARNING', 'fails for ' || v) " +
+"   WHEN true " +
+"   THEN javatest.logmessage('INFO', 'VarlenaUDTTest works for ' || v) " +
+"   ELSE javatest.logmessage('WARNING', 'VarlenaUDTTest fails for ' || v) " +
 "   END " +
 "   FROM (VALUES (('32767')), (('32768')), (('65536')), (('1048576'))) " +
 "   AS t ( v )"
diff --git a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/XMLRenderedTypes.java b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/XMLRenderedTypes.java
index 871e96445..812233d15 100644
--- a/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/XMLRenderedTypes.java
+++ b/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/XMLRenderedTypes.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2019-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -27,19 +27,23 @@
  *<p>
  * Everything mentioning the type XML here needs a conditional implementor tag
  * in case of being loaded into a PostgreSQL instance built without that type.
- * The {@code pg_node_tree} type appears in 9.1.
  */
-@SQLAction(implementor="postgresql_ge_90100",
-	provides="postgresql_xml_ge91",
-	install=
-	"SELECT CASE (SELECT 1 FROM pg_type WHERE typname = 'xml') WHEN 1" +
-	" THEN set_config('pljava.implementors', 'postgresql_xml_ge91,' || " +
-	" current_setting('pljava.implementors'), true) " +
-	"END"
+@SQLAction(implementor="postgresql_xml", requires="pgNodeTreeAsXML", install=
+"WITH" +
+"  a(t) AS (SELECT adbin FROM pg_catalog.pg_attrdef LIMIT 1)" +
+" SELECT" +
+"   CASE WHEN pgNodeTreeAsXML(t) IS DOCUMENT" +
+"    THEN javatest.logmessage('INFO', 'pgNodeTreeAsXML ok')" +
+"    ELSE javatest.logmessage('WARNING', 'pgNodeTreeAsXML ng')" +
+"   END" +
+"  FROM a"
 )
 public class XMLRenderedTypes
 {
-	@Function(schema="javatest", implementor="postgresql_xml_ge91")
+	@Function(
+		schema="javatest", implementor="postgresql_xml",
+		provides="pgNodeTreeAsXML"
+	)
 	public static SQLXML pgNodeTreeAsXML(@SQLType("pg_node_tree") SQLXML pgt)
 	throws SQLException
 	{
diff --git a/pljava-packaging/build.xml b/pljava-packaging/build.xml
index 0df763e78..fb8555cc4 100644
--- a/pljava-packaging/build.xml
+++ b/pljava-packaging/build.xml
@@ -255,6 +255,10 @@ jos.close();
 			     simple update is possible, just repeat the next entry, with
 				 the from-version changed.
 			  -->
+			<utf8 dir="target/classes" includes="pljava--.sql"
+				fullpath=
+			"pljava/sharedir/pljava/pljava--1.6.6--${project.version}.sql"
+			/>
 			<utf8 dir="target/classes" includes="pljava--.sql"
 				fullpath=
 			"pljava/sharedir/pljava/pljava--1.6.5--${project.version}.sql"
diff --git a/pljava-packaging/pom.xml b/pljava-packaging/pom.xml
index 8348726f8..a101c7fea 100644
--- a/pljava-packaging/pom.xml
+++ b/pljava-packaging/pom.xml
@@ -64,6 +64,23 @@
 			</properties>
 		</profile>
 
+		<!--
+		  - Activate this profile just as a convenient way to make Maven
+		  - download the pgjdbc driver. It isn't needed in any way for
+		  - building, but then you will have it in your local Maven repository
+		  - if you want to add it to your classpath for some tests.
+		  -->
+		<profile>
+			<id>pgjdbc</id>
+			<dependencies>
+				<dependency>
+					<groupId>org.postgresql</groupId>
+					<artifactId>postgresql</artifactId>
+					<version>[42.6.0,)</version>
+				</dependency>
+			</dependencies>
+		</profile>
+
 		<!--
 		  - Activate this profile just as a convenient way to make Maven
 		  - download the pgjdbc-ng driver. It isn't needed in any way for
diff --git a/pljava-packaging/src/main/java/Node.java b/pljava-packaging/src/main/java/Node.java
index 48deda9de..eb25fd406 100644
--- a/pljava-packaging/src/main/java/Node.java
+++ b/pljava-packaging/src/main/java/Node.java
@@ -32,8 +32,16 @@
 
 import static java.lang.ProcessBuilder.Redirect.INHERIT;
 import java.lang.reflect.InvocationHandler; // flexible SAM allowing exceptions
+import java.lang.reflect.UndeclaredThrowableException;
 import static java.lang.Thread.interrupted;
 
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles.Lookup;
+import static java.lang.invoke.MethodHandles.explicitCastArguments;
+import static java.lang.invoke.MethodHandles.filterReturnValue;
+import static java.lang.invoke.MethodHandles.publicLookup;
+import static java.lang.invoke.MethodType.methodType;
+
 import static java.net.InetAddress.getLoopbackAddress;
 import static java.net.URLEncoder.encode;
 import java.net.ServerSocket;
@@ -59,6 +67,7 @@
 import java.nio.file.NoSuchFileException;
 
 import java.sql.Connection;
+import static java.sql.DriverManager.drivers;
 import static java.sql.DriverManager.getConnection;
 import java.sql.ParameterMetaData;
 import java.sql.PreparedStatement;
@@ -90,6 +99,7 @@
 import static java.util.Spliterator.NONNULL;
 import static java.util.Spliterator.ORDERED;
 import static java.util.Spliterators.spliteratorUnknownSize;
+import java.util.WeakHashMap;
 
 import java.util.concurrent.Callable; // like a Supplier but allows exceptions!
 import java.util.concurrent.CancellationException;
@@ -109,7 +119,7 @@
 import static java.util.stream.StreamSupport.stream;
 
 /**
- * Subclass the JarX extraction tool to provide a {@code resolve} method that
+ * Extends the JarX extraction tool to provide a {@code resolve} method that
  * replaces prefixes {@code pljava/foo/} in path names stored in the archive
  * with the result of {@code pg_config --foo}.
  *<p>
@@ -118,16 +128,17 @@
  * useful for tasks related to installation and testing. The idea is not to go
  * overboard, but supply a few methods largely modeled on the most basic ones of
  * PostgreSQL's {@code PostgresNode.pm}, with the idea that they can be invoked
- * from {@code jshell} if its classpath includes the installer jar (and
- * pgjdbc-ng).
+ * from {@code jshell} if its classpath includes the installer jar (and one of
+ * the PostgreSQL JDBC drivers).
  *<p>
  * An
  * <a href="../../../../../../develop/node.html">introduction with examples</a>
  * is available.
  *<p>
  * Unlike the many capabilities of {@code PostgresNode.pm}, this only deals in
- * TCP sockets bound to {@code localhost} (Java doesn't have Unix sockets out of
- * the box yet) and only a few of the most basic operations.
+ * TCP sockets bound to {@code localhost} ({@code StandardProtocolFamily.UNIX}
+ * finally arrived in Java 16 but this class does not support it yet) and only
+ * a few of the most basic operations.
  *<p>
  * As in JarX itself, some liberties with coding style may be taken here to keep
  * this one extra {@code .class} file from proliferating into a bunch of them.
@@ -151,7 +162,7 @@ public class Node extends JarX {
 	private static String s_sharedObject;
 
 	/**
-	 * Perform an ordinary installation, using {@code pg_config} or the
+	 * Performs an ordinary installation, using {@code pg_config} or the
 	 * corresponding system properties to learn where the files belong, and
 	 * unpacking the files (not including this class or its ancestors) there.
 	 */
@@ -167,7 +178,7 @@ public static void main(String[] args) throws Exception
 	}
 
 	/**
-	 * Extract the jar contents, just as done in the normal case of running
+	 * Extracts the jar contents, just as done in the normal case of running
 	 * this class with {@code java -jar}.
 	 *<p>
 	 * Only to be called on the singleton instance {@code s_jarxHelper}.
@@ -184,7 +195,7 @@ public void extract() throws Exception
 	}
 
 	/**
-	 * Prepare the resolver, ignoring the passed string (ordinarily a script or
+	 * Prepares the resolver, ignoring the passed string (ordinarily a script or
 	 * rules); this resolver's rules are hardcoded.
 	 */
 	@Override
@@ -289,6 +300,166 @@ else if ( storedPath.matches(
 	public static final boolean s_isWindows =
 		getProperty("os.name").startsWith("Windows");
 
+	/**
+	 * The first form of PostgreSQL JDBC driver connection URL found to be
+	 * recognized by an available driver, or {@code URL_FORM_NONE}.
+	 */
+	public static final int s_urlForm;
+
+	/**
+	 * Value of {@link #s_urlForm s_urlForm} indicating no available JDBC driver
+	 * was found to accept any of the supported connection URL forms.
+	 */
+	public static final int URL_FORM_NONE = -1;
+
+	/**
+	 * Value of {@link #s_urlForm s_urlForm} indicating an available JDBC driver
+	 * reported accepting a connection URL in the PGJDBC form starting with
+	 * {@code "jdbc:postgresql:"}.
+	 */
+	public static final int URL_FORM_PGJDBC = 0;
+
+	/**
+	 * Value of {@link #s_urlForm s_urlForm} indicating an available JDBC driver
+	 * reported accepting a connection URL in the pgjdbc-ng form starting with
+	 * {@code "jdbc:pgsql:"}.
+	 */
+	public static final int URL_FORM_PGJDBCNG = 1;
+
+	/**
+	 * A function to map an {@code SQLWarning} to a rough classification
+	 * (info, warning) of its severity.
+	 *<p>
+	 * If the PGJDBC {@code PSQLWarning} class is available for access to the
+	 * severity tag from the backend, "warning" will be returned if that tag is
+	 * {@code WARNING}, and "info" will be returned in any other case. (The next
+	 * more severe backup level is {@code ERROR}, which would not appear here as
+	 * an {@code SQLWarning}.)
+	 *<p>
+	 * If the severity tag is not available, "info" will be returned if the
+	 * class (leftmost two positions of SQLState) is 00, otherwise "warning".
+	 */
+	private static final Function<SQLWarning,String> s_toSeverity;
+
+	private static String s_WARNING_localized = "WARNING";
+
+	/**
+	 * Changes the severity string used to recognize when the backend is sending
+	 * a {@code WARNING}.
+	 *<p>
+	 * When the driver is PGJDBC, the classification done here of
+	 * {@code SQLWarning} instances into actual warning messages or informative
+	 * ones depends on a tag ("WARNING" in English) that the backend delivers
+	 * in the local language. For the classification to happen correctly when
+	 * a different language is selected, use this method to supply the string
+	 * (for example, "PERINGATAN" in Indonesian) that the backend uses for
+	 * warnings in that language.
+	 */
+	public static void set_WARNING_localized(String s)
+	{
+		s_WARNING_localized = requireNonNull(s);
+	}
+
+	static
+	{
+		String[] candidateURLs = { "jdbc:postgresql:", "jdbc:pgsql:x" };
+		s_urlForm =
+			IntStream.range(0, candidateURLs.length)
+				.filter(i ->
+					drivers().anyMatch(d ->
+					{
+						try
+						{
+							return d.acceptsURL(candidateURLs[i]);
+						}
+						catch ( SQLException e )
+						{
+							throw new ExceptionInInitializerError(e);
+						}
+					}))
+				.findFirst()
+				.orElse(URL_FORM_NONE);
+
+		Function<SQLWarning,String> toSeverity = Node::toSeverityFallback;
+
+		try
+		{
+			Class<?> psqlWarning =
+				Class.forName("org.postgresql.util.PSQLWarning");
+			Class<?> sErrMessage =
+				Class.forName("org.postgresql.util.ServerErrorMessage");
+
+			Lookup pub = publicLookup();
+
+			MethodHandle getserrm =
+				pub.findVirtual(psqlWarning, "getServerErrorMessage",
+					methodType(sErrMessage));
+			MethodHandle getSev =
+				pub.findVirtual(sErrMessage, "getSeverity",
+					methodType(String.class));
+
+			MethodHandle h = explicitCastArguments(
+				filterReturnValue(getserrm, getSev),
+				methodType(String.class, Object.class));
+
+			toSeverity = w ->
+			{
+				if ( psqlWarning.isInstance(w) )
+				{
+					try
+					{
+						String s = (String)h.invokeExact(psqlWarning.cast(w));
+						if ( null == s  ||  s_WARNING_localized.equals(s) )
+							return "warning";
+						return "info";
+					}
+					catch ( Throwable t )
+					{
+						throw new UndeclaredThrowableException(t, t.getMessage());
+					}
+				}
+
+				return toSeverityFallback(w);
+			};
+		}
+		catch ( ReflectiveOperationException e )
+		{
+		}
+
+		s_toSeverity = toSeverity;
+	}
+
+	private static String toSeverityFallback(SQLWarning w)
+	{
+		if ( w.getSQLState().startsWith("00") )
+			return "info";
+		else
+			return "warning";
+	}
+
+	/**
+	 * A state (see {@link #stateMachine stateMachine}) that expects nothing
+	 * (if the driver is pgjdbc-ng) or a zero row count (if the driver is
+	 * PGJDBC).
+	 *<p>
+	 * For some utility statements (such as {@code CREATE EXTENSION}) with no
+	 * result, the pgjdbc-ng driver will produce no result, while the PGJDBC
+	 * driver produces a zero count, as it would for a DML statement that did
+	 * not affect any rows. This state handles either case.
+	 *<p>
+	 * When {@code URL_FORM_PGJDBCNG == s_urlForm}, this state consumes nothing
+	 * and moves to the numerically next state. Otherwise (JDBC), it checks
+	 * that the current object is a zero row count, consuming it and moving to
+	 * the numerically next state if it is, returning false otherwise.
+	 */
+	public static final InvocationHandler NOTHING_OR_PGJDBC_ZERO_COUNT=(o,p,q)->
+	{
+		int myStateNum = (int)q[0];
+		if ( URL_FORM_PGJDBCNG == s_urlForm )
+			return -(1 + myStateNum);
+		return 0 == as(Long.class, o) ? 1 + myStateNum : false;
+	};
+
 	/**
 	 * Name of a "Node"; null for an ordinary Node instance.
 	 */
@@ -347,6 +518,26 @@ else if ( storedPath.matches(
 	 */
 	private boolean m_usePostgres = true;
 
+	/**
+	 * A weakly-held collection of {@link Connection}s, so that any remaining
+	 * unclosed when {@link #stop(UnaryOperator) stop} is called can be closed
+	 * then.
+	 *<p>
+	 * Java takes care of removing {@code Connection}s from this map as they
+	 * become unreachable. In case any become unreachable before being closed,
+	 * both supported JDBC drivers have cleaner actions that will eventually
+	 * close them.
+	 */
+	private final WeakHashMap<Connection,Void> m_connections;
+
+	/**
+	 * True during a {@link #stop(UnaryOperator) stop} call.
+	 *<p>
+	 * Used to prevent any new unclosed {@code Connection} being added to
+	 * {@link m_connections m_connections} undetected.
+	 */
+	private boolean m_stopping = false;
+
 	/**
 	 * Identifying information for a "node" instance, or for the singleton
 	 * extractor instance.
@@ -360,7 +551,7 @@ public String toString()
 	}
 
 	/**
-	 * Construct an instance; all nulls for the parameters are passed by the
+	 * Constructs an instance; all nulls for the parameters are passed by the
 	 * static initializer to make the singleton extractor instance, and any
 	 * other instance is constructed by {@code get_new_node} for controlling
 	 * a PostgreSQL instance.
@@ -371,10 +562,11 @@ private Node(String nodeName, int port, Path basedir, String password)
 		m_port = port;
 		m_basedir = basedir;
 		m_password = password;
+		m_connections = null == nodeName ? null : new WeakHashMap<>();
 	}
 
 	/**
-	 * Return a new {@code Node} that can be used to initialize and start a
+	 * Returns a new {@code Node} that can be used to initialize and start a
 	 * PostgreSQL instance.
 	 *<p>
 	 * Establishes a VM shutdown hook that will stop the server (if started)
@@ -407,7 +599,7 @@ public static Node get_new_node(String name) throws Exception
 	}
 
 	/**
-	 * Return a TCP port on the loopback interface that is free at the moment
+	 * Returns a TCP port on the loopback interface that is free at the moment
 	 * this method is called.
 	 */
 	public static int get_free_port() throws Exception
@@ -419,7 +611,7 @@ public static int get_free_port() throws Exception
 	}
 
 	/**
-	 * Recursively remove the <em>basedir</em> and its descendants.
+	 * Recursively removes the <em>basedir</em> and its descendants.
 	 */
 	public void clean_node() throws Exception
 	{
@@ -427,7 +619,8 @@ public void clean_node() throws Exception
 	}
 
 	/**
-	 * Recursively remove the <em>basedir</em> and its descendants.
+	 * Recursively removes the <em>basedir</em> (unless <var>keepRoot</var>)
+	 * and its descendants.
 	 * @param keepRoot if true, the descendants are removed, but not the basedir
 	 * itself.
 	 */
@@ -466,7 +659,8 @@ public void clean_node(boolean keepRoot) throws Exception
 	}
 
 	/**
-	 * Process the jar without really extracting, to compute the path mappings.
+	 * Processes the jar without really extracting, to compute
+	 * the path mappings.
 	 */
 	private static void dryExtract() throws Exception
 	{
@@ -487,7 +681,7 @@ private static void dryExtract() throws Exception
 	 * Given a path from the archive, or any path <em>resembling</em> one in
 	 * the archive (that is, always {@code /} as the separator, and starting
 	 * with {@code pljava/}<em>key</em> where {@code --}<em>key</em> is known
-	 * to {@code pg_config}, return the platform-specific path where it would
+	 * to {@code pg_config}, returns the platform-specific path where it would
 	 * be installed.
 	 */
 	private static String resolve(String archivePath) throws Exception
@@ -497,7 +691,7 @@ private static String resolve(String archivePath) throws Exception
 	}
 
 	/**
-	 * Return the directory name to be used as the PostgreSQL data directory
+	 * Returns the directory name to be used as the PostgreSQL data directory
 	 * for this node.
 	 */
 	public Path data_dir()
@@ -530,7 +724,8 @@ public AutoCloseable initialized_cluster(Map<String,String> suppliedOptions)
 	}
 
 	/**
-	 * Like {@code init()} but returns an {@code AutoCloseable} that will
+	 * Like {@link #init(Map,UnaryOperator) init()} but returns
+	 * an {@code AutoCloseable} that will
 	 * recursively remove the files and directories under the <em>basedir</em>
 	 * (but not the <em>basedir</em> itself) on the exit of a calling
 	 * try-with-resources scope.
@@ -543,7 +738,8 @@ public AutoCloseable initialized_cluster(
 	}
 
 	/**
-	 * Like {@code init()} but returns an {@code AutoCloseable} that will
+	 * Like {@link #init(Map,UnaryOperator) init()} but returns
+	 * an {@code AutoCloseable} that will
 	 * recursively remove the files and directories under the <em>basedir</em>
 	 * (but not the <em>basedir</em> itself) on the exit of a calling
 	 * try-with-resources scope.
@@ -561,7 +757,7 @@ public AutoCloseable initialized_cluster(
 	}
 
 	/**
-	 * Invoke {@code initdb} for the node, passing default options appropriate
+	 * Invokes {@code initdb} for the node, passing default options appropriate
 	 * for this setting.
 	 */
 	public void init() throws Exception
@@ -570,7 +766,7 @@ public void init() throws Exception
 	}
 
 	/**
-	 * Invoke {@code initdb} for the node, with <em>suppliedOptions</em>
+	 * Invokes {@code initdb} for the node, with <em>suppliedOptions</em>
 	 * overriding or supplementing the ones that would be passed by default.
 	 */
 	public void init(Map<String,String> suppliedOptions) throws Exception
@@ -579,9 +775,9 @@ public void init(Map<String,String> suppliedOptions) throws Exception
 	}
 
 	/**
-	 * Invoke {@code initdb} for the node, passing default options appropriate
-	 * for this setting, and tweaks to be applied to the
-	 * {@code ProcessBuilder} before it is started.
+	 * Invokes {@code initdb} for the node, passing default options appropriate
+	 * for this setting, and {@linkplain #init(Map,UnaryOperator) tweaks} to be
+	 * applied to the {@code ProcessBuilder} before it is started.
 	 */
 	public void init(UnaryOperator<ProcessBuilder> tweaks) throws Exception
 	{
@@ -589,7 +785,7 @@ public void init(UnaryOperator<ProcessBuilder> tweaks) throws Exception
 	}
 
 	/**
-	 * Invoke {@code initdb} for the node, with <em>suppliedOptions</em>
+	 * Invokes {@code initdb} for the node, with <em>suppliedOptions</em>
 	 * overriding or supplementing the ones that would be passed by default,
 	 * and <em>tweaks</em> to be applied to the {@code ProcessBuilder}
 	 * before it is started.
@@ -605,7 +801,9 @@ public void init(UnaryOperator<ProcessBuilder> tweaks) throws Exception
 	 * @param suppliedOptions a Map where each key is an option to initdb
 	 * (for example, --encoding), and the value corresponds.
 	 * @param tweaks a lambda applicable to the {@code ProcessBuilder} to
-	 * further configure it.
+	 * further configure it. On Windows, the tweaks will be applied ahead of
+	 * transformation of the arguments by
+	 * {@link #forWindowsCRuntime forWindowsCRuntime}.
 	 */
 	public void init(
 		Map<String,String> suppliedOptions,
@@ -699,8 +897,13 @@ public AutoCloseable started_server(Map<String,String> suppliedOptions)
 	}
 
 	/**
-	 * Like {@code start()} but returns an {@code AutoCloseable} that will
+	 * Like {@link #start(Map,UnaryOperator) start()} but returns
+	 * an {@code AutoCloseable} that will
 	 * stop the server on the exit of a calling try-with-resources scope.
+	 *<p>
+	 * Supplied <em>tweaks</em> will be applied to the {@code ProcessBuilder}
+	 * used to start the server; if {@code pg_ctl} is being used, they will also
+	 * be applied when running {@code pg_ctl stop} to stop it.
 	 */
 	public AutoCloseable started_server(UnaryOperator<ProcessBuilder> tweaks)
 	throws Exception
@@ -709,7 +912,8 @@ public AutoCloseable started_server(UnaryOperator<ProcessBuilder> tweaks)
 	}
 
 	/**
-	 * Like {@code start()} but returns an {@code AutoCloseable} that will
+	 * Like {@link #start(Map,UnaryOperator) start()} but returns
+	 * an {@code AutoCloseable} that will
 	 * stop the server on the exit of a calling try-with-resources scope.
 	 *<p>
 	 * Supplied <em>tweaks</em> will be applied to the {@code ProcessBuilder}
@@ -729,7 +933,7 @@ public AutoCloseable started_server(
 	}
 
 	/**
-	 * Start a PostgreSQL server for the node with default options appropriate
+	 * Starts a PostgreSQL server for the node with default options appropriate
 	 * for this setting.
 	 */
 	public void start() throws Exception
@@ -738,7 +942,7 @@ public void start() throws Exception
 	}
 
 	/**
-	 * Start a PostgreSQL server for the node, with <em>suppliedOptions</em>
+	 * Starts a PostgreSQL server for the node, with <em>suppliedOptions</em>
 	 * overriding or supplementing the ones that would be passed by default.
 	 */
 	public void start(Map<String,String> suppliedOptions) throws Exception
@@ -747,8 +951,9 @@ public void start(Map<String,String> suppliedOptions) throws Exception
 	}
 
 	/**
-	 * Start a PostgreSQL server for the node, passing default options
-	 * appropriate for this setting, and tweaks to be
+	 * Starts a PostgreSQL server for the node, passing default options
+	 * appropriate for this setting, and
+	 * {@linkplain #start(Map,UnaryOperator) tweaks} to be
 	 * applied to the {@code ProcessBuilder} before it is started.
 	 */
 	public void start(UnaryOperator<ProcessBuilder> tweaks) throws Exception
@@ -757,7 +962,7 @@ public void start(UnaryOperator<ProcessBuilder> tweaks) throws Exception
 	}
 
 	/**
-	 * Start a PostgreSQL server for the node, with <em>suppliedOptions</em>
+	 * Starts a PostgreSQL server for the node, with <em>suppliedOptions</em>
 	 * overriding or supplementing the ones that would be passed by default, and
 	 * <em>tweaks</em> to be applied to the {@code ProcessBuilder} before it
 	 * is started.
@@ -779,7 +984,11 @@ public void start(UnaryOperator<ProcessBuilder> tweaks) throws Exception
 	 * name as seen in {@code postgresql.conf} or passed to the server with
 	 * {@code -c} and the value corresponds.
 	 * @param tweaks a lambda applicable to the {@code ProcessBuilder} to
-	 * further configure it.
+	 * further configure it. Under {@link #use_pg_ctl use_pg_ctl(true)}, the
+	 * tweaks are applied after the arguments have been transformed by
+	 * {@link #asPgCtlInvocation asPgCtlInvocation}. On Windows, they are
+	 * applied ahead of transformation of the arguments by
+	 * {@link #forWindowsCRuntime forWindowsCRuntime}.
 	 */
 	public void start(
 		Map<String,String> suppliedOptions,
@@ -853,7 +1062,7 @@ public void start(
 
 
 	/**
-	 * Stop the server instance associated with this Node.
+	 * Stops the server instance associated with this Node.
 	 *<p>
 	 * Has the effect of {@link #stop(UnaryOperator) stop(tweaks)} without
 	 * any tweaks.
@@ -864,33 +1073,67 @@ public void stop() throws Exception
 	}
 
 	/**
-	 * Stop the server instance associated with this Node.
+	 * Stops the server instance associated with this Node.
 	 *<p>
 	 * No effect if it has not been started or has already been stopped, but
 	 * a message to standard error is logged if the server had been started and
 	 * the process is found to have exited unexpectedly.
-	 * @param tweaks tweaks to apply to a ProcessBuilder; unused unless pg_ctl
-	 * will be used to stop the server
+	 * @param tweaks tweaks to apply to a ProcessBuilder; unused unless
+	 * {@code pg_ctl} will be used to stop the server. When used, they are
+	 * applied ahead of the transformation of the arguments by
+	 * {@link #forWindowsCRuntime forWindowsCRuntime} used on Windows.
 	 */
 	public void stop(UnaryOperator<ProcessBuilder> tweaks) throws Exception
 	{
 		if ( null == ( m_usePostgres ? m_server : m_serverHandle ) )
 			return;
-		if ( ! m_usePostgres )
+
+		try
 		{
-			stopViaPgCtl(tweaks);
-			return;
+			Connection[] connections;
+
+			synchronized ( this )
+			{
+				m_stopping = true;
+				connections = // Java >= 10: use a List and List.copyOf
+					m_connections.keySet().stream().toArray(Connection[]::new);
+				m_connections.clear();
+			}
+
+			for ( Connection c : connections )
+			{
+				try
+				{
+					c.close();
+				}
+				catch ( Exception e )
+				{
+				}
+			}
+
+			if ( ! m_usePostgres )
+			{
+				stopViaPgCtl(tweaks);
+				return;
+			}
+			if ( m_server.isAlive() )
+			{
+				m_server.destroy();
+				m_server.waitFor();
+				m_server = null;
+				return;
+			}
+			System.err.println("Server had already exited with status " +
+				m_server.exitValue());
+			m_server = null;
 		}
-		if ( m_server.isAlive() )
+		finally
 		{
-			m_server.destroy();
-			m_server.waitFor();
-			m_server = null;
-			return;
+			synchronized ( this )
+			{
+				m_stopping = false;
+			}
 		}
-		System.err.println("Server had already exited with status " +
-			m_server.exitValue());
-		m_server = null;
 	}
 
 	private void stopViaPgCtl(UnaryOperator<ProcessBuilder> tweaks)
@@ -909,6 +1152,10 @@ private void stopViaPgCtl(UnaryOperator<ProcessBuilder> tweaks)
 			.redirectOutput(INHERIT)
 			.redirectError(INHERIT);
 		pb = tweaks.apply(pb);
+
+		if ( s_isWindows )
+			pb = forWindowsCRuntime(pb);
+
 		Process p = pb.start();
 		p.getOutputStream().close();
 
@@ -935,7 +1182,7 @@ private void stopViaPgCtl(UnaryOperator<ProcessBuilder> tweaks)
 	}
 
 	/**
-	 * Indicate whether to use {@code pg_ctl} to start and stop the server
+	 * Sets whether to use {@code pg_ctl} to start and stop the server
 	 * (if true), or start {@code postgres} and stop it directly (if false,
 	 * the default).
 	 *<p>
@@ -952,7 +1199,7 @@ public void use_pg_ctl(boolean setting)
 	}
 
 	/**
-	 * Return a {@code Connection} to the server associated with this Node,
+	 * Returns a {@code Connection} to the server associated with this Node,
 	 * using default properties appropriate for this setting.
 	 */
 	public Connection connect() throws Exception
@@ -961,7 +1208,7 @@ public Connection connect() throws Exception
 	}
 
 	/**
-	 * Return a {@code Connection} to the server associated with this Node,
+	 * Returns a {@code Connection} to the server associated with this Node,
 	 * with <em>suppliedProperties</em> overriding or supplementing the ones
 	 * that would be passed by default.
 	 */
@@ -974,7 +1221,7 @@ public Connection connect(Map<String,String> suppliedProperties)
 	}
 
 	/**
-	 * Return a {@code Connection} to the server associated with this Node,
+	 * Returns a {@code Connection} to the server associated with this Node,
 	 * with supplied properties <em>p</em> overriding or supplementing the ones
 	 * that would be passed by default.
 	 *<p>
@@ -985,28 +1232,71 @@ public Connection connect(Map<String,String> suppliedProperties)
 	 */
 	public Connection connect(Properties p) throws Exception
 	{
-		String url = "jdbc:pgsql://localhost:" + m_port + '/';
+		String url;
+		String dbNameKey;
+		String appNameKey;
+
+		switch ( s_urlForm )
+		{
+		case URL_FORM_PGJDBC:
+			url = "jdbc:postgresql://localhost:" + m_port + '/';
+			dbNameKey = "PGDBNAME";
+			appNameKey = "ApplicationName";
+			break;
+		case URL_FORM_PGJDBCNG:
+			url = "jdbc:pgsql://localhost:" + m_port + '/';
+			dbNameKey = "database.name";
+			appNameKey = "application.name";
+			break;
+		default:
+			throw new UnsupportedOperationException(
+				"no recognized JDBC driver found to connect to the node");
+		}
+
 		p = (Properties)p.clone();
-		p.putIfAbsent("database.name", "postgres");
+		p.putIfAbsent(dbNameKey, "postgres");
 		p.putIfAbsent("user", "postgres");
 		p.putIfAbsent("password", m_password);
-		p.computeIfAbsent("application.name", o -> "Conn" + (m_connCount++));
-		/*
-		 * Contrary to its documentation, pgjdbc-ng does *not* accept a URL with
-		 * the database name omitted. It is no use having it in the properties
-		 * here; it must be appended to the URL.
-		 */
-		url += encode(p.getProperty("database.name"), "UTF-8");
-		return getConnection(url, p);
+		p.computeIfAbsent(appNameKey, o -> "Conn" + (m_connCount++));
+
+		if ( URL_FORM_PGJDBCNG == s_urlForm )
+		{
+			/*
+			 * Contrary to its documentation, pgjdbc-ng does *not* accept a URL
+			 * with the database name omitted. It is no use having it in the
+			 * properties here; it must be appended to the URL.
+			 */
+			url += encode(p.getProperty(dbNameKey), "UTF-8");
+		}
+
+		Connection c = getConnection(url, p);
+
+		synchronized ( this )
+		{
+			if ( m_stopping )
+			{
+				try
+				{
+					throw new IllegalStateException(
+						"Node " + m_name + " is being stopped");
+				}
+				finally
+				{
+					c.close(); // add any exception as 'suppressed' to above
+				}
+			}
+			m_connections.put(c, null);
+			return c;
+		}
 	}
 
 	/**
-	 * Set a configuration variable on the server.
+	 * Sets a configuration variable on the server.
 	 *<p>
 	 * This deserves a convenience method because the most familiar PostgreSQL
 	 * syntax for SET doesn't lend itself to parameterization.
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> setConfig(
 		Connection c, String settingName, String newValue, boolean isLocal)
@@ -1021,7 +1311,8 @@ public static Stream<Object> setConfig(
 	}
 
 	/**
-	 * Load PL/Java (with a {@code LOAD} command, not {@code CREATE EXTENSION}).
+	 * Loads PL/Java (with a {@code LOAD} command,
+	 * not {@code CREATE EXTENSION}).
 	 *<p>
 	 * This was standard procedure in PostgreSQL versions that pre-dated the
 	 * extension support. It is largely obsolete with the advent of
@@ -1033,8 +1324,12 @@ public static Stream<Object> setConfig(
 	 * that {@code pljava.module_path} is set correctly to locate the jar files,
 	 * and give the correct shared-object path to {@code LOAD} (which this
 	 * method does).
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 *<p>
+	 * It is also useful to see better diagnostics if something is going wrong,
+	 * as PostgreSQL severely suppresses diagnostic messages during
+	 * {@code CREATE EXTENSION}.
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> loadPLJava(Connection c) throws Exception
 	{
@@ -1054,9 +1349,9 @@ public static Stream<Object> loadPLJava(Connection c) throws Exception
 	}
 
 	/**
-	 * Install a jar.
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * Installs a jar.
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> installJar(
 		Connection c, String uri, String jarName, boolean deploy)
@@ -1071,9 +1366,9 @@ public static Stream<Object> installJar(
 	}
 
 	/**
-	 * Remove a jar.
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * Removes a jar.
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> removeJar(
 		Connection c, String jarName, boolean undeploy)
@@ -1087,9 +1382,9 @@ public static Stream<Object> removeJar(
 	}
 
 	/**
-	 * Set the class path for a schema.
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * Sets the class path for a schema.
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> setClasspath(
 		Connection c, String schema, String... jarNames)
@@ -1103,10 +1398,11 @@ public static Stream<Object> setClasspath(
 	}
 
 	/**
-	 * Append a jar to a schema's class path if not already included.
-	 * @return a {@link #q(Statement,Callable) result stream} that includes, on
-	 * success, a one-column {@code void} result set with a single row if the
-	 * jar was added to the path, and no rows if the jar was already included.
+	 * Appends a jar to a schema's class path if not already included.
+	 * @return a {@linkplain #q(Statement,Callable) result stream} that
+	 * includes, on success, a one-column {@code void} result set with a single
+	 * row if the jar was added to the path, and no rows if the jar was already
+	 * included.
 	 */
 	public static Stream<Object> appendClasspathIf(
 		Connection c, String schema, String jarName)
@@ -1139,9 +1435,9 @@ public static Stream<Object> appendClasspathIf(
 	}
 
 	/**
-	 * Execute some arbitrary SQL
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * Executes some arbitrary SQL
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> q(Connection c, String sql) throws Exception
 	{
@@ -1522,8 +1818,8 @@ public static Stream<Object> q(final ParameterMetaData pmd)
 	}
 
 	/**
-	 * Execute some arbitrary SQL and pass
-	 * the {@link #q(Statement,Callable) result stream}
+	 * Executes some arbitrary SQL and passes
+	 * the {@linkplain #q(Statement,Callable) result stream}
 	 * to {@link #qp(Stream)} for printing to standard output.
 	 */
 	public static void qp(Connection c, String sql) throws Exception
@@ -1532,8 +1828,8 @@ public static void qp(Connection c, String sql) throws Exception
 	}
 
 	/**
-	 * Invoke some {@code execute} method on a {@code Statement} and pass
-	 * the {@link #q(Statement,Callable) result stream}
+	 * Invokes some {@code execute} method on a {@code Statement} and passes
+	 * the {@linkplain #q(Statement,Callable) result stream}
 	 * to {@link #qp(Stream)} for printing to standard output.
 	 *<p>
 	 * This is how, for example, to prepare, then print the results of, a
@@ -1552,7 +1848,7 @@ public static void qp(Statement s, Callable<Boolean> work) throws Exception
 	}
 
 	/**
-	 * Return true if the examples jar includes the
+	 * Returns true if the examples jar includes the
 	 * {@code org.postgresql.pljava.example.saxon.S9} class (meaning the
 	 * appropriate Saxon jar must be installed and on the classpath first before
 	 * the examples jar can be deployed, unless {@code check_function_bodies}
@@ -1570,12 +1866,12 @@ public static boolean examplesNeedSaxon() throws Exception
 	}
 
 	/**
-	 * Install the examples jar, under the name {@code examples}.
+	 * Installs the examples jar, under the name {@code examples}.
 	 *<p>
 	 * The jar is specified by a {@code file:} URI and the path is the one where
 	 * this installer installed (or would have installed) it.
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> installExamples(Connection c, boolean deploy)
 	throws Exception
@@ -1587,15 +1883,15 @@ public static Stream<Object> installExamples(Connection c, boolean deploy)
 	}
 
 	/**
-	 * Install the examples jar, under the name {@code examples}, and append it
-	 * to the class path for schema {@code public}.
+	 * Installs the examples jar, under the name {@code examples}, and appends
+	 * it to the class path for schema {@code public}.
 	 *<p>
 	 * The return of a concatenated result stream from two consecutive
 	 * statements might be likely to fail in cases where the first
-	 * statement has any appreciable data to return, but pgjdbc-ng seems to
+	 * statement has any appreciable data to return, but the drivers seem to
 	 * handle it at least in this case where each statement just returns one
 	 * row / one column of {@code void}. And it is convenient.
-	 * @return a combined {@link #q(Statement,Callable) result stream} from
+	 * @return a combined {@linkplain #q(Statement,Callable) result stream} from
 	 * executing the statements
 	 */
 	public static Stream<Object> installExamplesAndPath(
@@ -1608,11 +1904,11 @@ public static Stream<Object> installExamplesAndPath(
 	}
 
 	/**
-	 * Install a Saxon jar under the name {@code saxon}, given the path to a
+	 * Installs a Saxon jar under the name {@code saxon}, given the path to a
 	 * local Maven repo and the needed version of Saxon, assuming the jar has
 	 * been downloaded there already.
-	 * @return a {@link #q(Statement,Callable) result stream} from executing
-	 * the statement
+	 * @return a {@linkplain #q(Statement,Callable) result stream} from
+	 * executing the statement
 	 */
 	public static Stream<Object> installSaxon(
 		Connection c, String repo, String version)
@@ -1625,9 +1921,9 @@ public static Stream<Object> installSaxon(
 	}
 
 	/**
-	 * Install a Saxon jar under the name {@code saxon}, and append it to the
+	 * Installs a Saxon jar under the name {@code saxon}, and appends it to the
 	 * class path for schema {@code public}.
-	 * @return a combined {@link #q(Statement,Callable) result stream} from
+	 * @return a combined {@linkplain #q(Statement,Callable) result stream} from
 	 * executing the statements
 	 */
 	public static Stream<Object> installSaxonAndPath(
@@ -1640,13 +1936,13 @@ public static Stream<Object> installSaxonAndPath(
 	}
 
 	/**
-	 * A four-fer: install Saxon, add it to the class path, then install the
-	 * examples jar, and update the classpath to include both.
+	 * A four-fer: installs Saxon, adds it to the class path, then installs the
+	 * examples jar, and updates the classpath to include both.
 	 * @param repo the base directory of a local Maven repository into which the
 	 * Saxon jar has been downloaded
 	 * @param version the needed version of Saxon
 	 * @param deploy whether to run the example jar's deployment code
-	 * @return a combined {@link #q(Statement,Callable) result stream} from
+	 * @return a combined {@linkplain #q(Statement,Callable) result stream} from
 	 * executing the statements
 	 */
 	public static Stream<Object> installSaxonAndExamplesAndPath(
@@ -1709,7 +2005,7 @@ else if ( oneResult instanceof SQLException )
 	}
 
 	/**
-	 * Print streamed results of a {@code Statement} in (somewhat) readable
+	 * Prints streamed results of a {@code Statement} in (somewhat) readable
 	 * fashion.
 	 *<p>
 	 * Uses {@code writeXml} of {@code WebRowSet}, which is very verbose, but
@@ -1727,7 +2023,7 @@ public static void qp(Stream<Object> s) throws Exception
 	}
 
 	/**
-	 * Print streamed results of a {@code Statement} in (somewhat) readable
+	 * Prints streamed results of a {@code Statement} in (somewhat) readable
 	 * fashion, with a choice of flattener for diagnostics.
 	 *<p>
 	 * For <em>flattener</em>, see {@link flattenDiagnostics flattenDiagnostics}
@@ -1783,7 +2079,7 @@ public static void peek(Object o)
 	{
 		try
 		{
-			int[] dims = voidResultSetDims(o);
+			int[] dims = voidResultSetDims(o, true); // only peek
 
 			if ( null != dims )
 			{
@@ -1924,14 +2220,14 @@ private static void qp(RowSetMetaDataImpl mdi) throws Exception
 	}
 
 	/**
-	 * Print a {@code Throwable} retrieved from a result stream, with
+	 * Prints a {@code Throwable} retrieved from a result stream, with
 	 * special handling for {@code SQLException} and {@code SQLWarning}.
 	 *<p>
 	 * In keeping with the XMLish vibe established by
 	 * {@link #qp(Stream) qp} for other items in a result
 	 * stream, this will render a {@code Throwable} as an {@code error},
 	 * {@code warning}, or {@code info} element (PostgreSQL's finer
-	 * distinctions of severity are not exposed by pgjdbc-ng's API.)
+	 * distinctions of severity are not exposed by every JDBC driver's API.)
 	 *<p>
 	 * An element will have a {@code message} attribute if it has a message.
 	 * It will have a {@code code} attribute containing the SQLState, if it is
@@ -1953,8 +2249,8 @@ public static void qp(Throwable t)
 	}
 
 	/**
-	 * Return an array of three {@code String}s, element, sqlState, and message,
-	 * as would be printed by {@link #qp(Throwable)}.
+	 * Returns an array of three {@code String}s, element, sqlState,
+	 * and message, as would be printed by {@link #qp(Throwable)}.
 	 *<p>
 	 * The first string will be: (1) if the throwable is an {@code SQLWarning},
 	 * "info" if its class (leftmost two positions of SQLState) is 00, otherwise
@@ -1967,6 +2263,12 @@ public static void qp(Throwable t)
 	 *<p>
 	 * The third string will be as returned by {@code getMessage}, and may be
 	 * null if the throwable was not constructed with a message.
+	 *<p>
+	 * If an {@code SQLWarning} is of the PGJDBC driver's {@code PSQLWarning}
+	 * class and the backend's severity tag is available, it will be used to
+	 * determine the first string, in place of the "starts with 00" rule. A tag
+	 * of "WARNING" (or null) produces "warning", while any other tag produces
+	 * "info".
 	 */
 	public static String[] classify(Throwable t)
 	{
@@ -1978,25 +2280,20 @@ public static String[] classify(Throwable t)
 			sqlState = ((SQLException)t).getSQLState();
 			if ( t instanceof SQLWarning )
 			{
-				if ( sqlState.startsWith("00") )
-				{
-					element = "info";
-					if ( "00000".equals(sqlState) )
+				element = s_toSeverity.apply((SQLWarning)t);
+				if ( "info".equals(element) && "00000".equals(sqlState) )
 						sqlState = null;
-				}
-				else
-					element = "warning";
 			}
 		}
 		return new String[] { element, sqlState, msg };
 	}
 
 	/**
-	 * Escape a string as an XML attribute.
+	 * Escapes a string as an XML attribute.
 	 *<p>
 	 * Right on the borderline of trivial enough to implement here rather than
-	 * forcing the beleaguered user to add yet one more --add-modules for
-	 * {@code java.xml} just to run this in {@code jshell}.
+	 * using `java.xml` APIs (even though those are available in `jshell` too,
+	 * transitively supplied by our reliance on `java.sql`).
 	 */
 	private static String asAttribute(String s)
 	{
@@ -2038,9 +2335,13 @@ else if ( '"' == c )
 	 * If this method returns non-null, the result set is left positioned on its
 	 * last row.
 	 * @param o Object to check
+	 * @param peek whether to avoid moving the row cursor. If true, and all of
+	 * the columns are indeed void, the result array will have the column count
+	 * at index 1 and -1 at index 0.
 	 * @return null or a two-element int[], as described above
 	 */
-	public static int[] voidResultSetDims(Object o) throws Exception
+	public static int[] voidResultSetDims(Object o, boolean peek)
+	throws Exception
 	{
 		if ( ! (o instanceof ResultSet) )
 			return null;
@@ -2048,18 +2349,40 @@ public static int[] voidResultSetDims(Object o) throws Exception
 		ResultSet rs = (ResultSet)o;
 		ResultSetMetaData md = rs.getMetaData();
 		int cols = md.getColumnCount();
+		int rows = 0;
 
 		for ( int c = 1; c <= cols; ++c )
 			if ( Types.OTHER != md.getColumnType(c)
 				||  ! "void".equals(md.getColumnTypeName(c)) )
 				return null;
 
-		rs.last(); // last(), getRow() appears to work, in pgjdbc-ng
-		return new int[] { rs.getRow(), cols };
+		if ( peek )
+			rows = -1;
+		else if ( URL_FORM_PGJDBCNG == s_urlForm )
+		{
+			rs.last(); // last(), getRow() appears to work, in pgjdbc-ng
+			rows = rs.getRow();
+		}
+		else
+		{
+			while ( rs.next() ) // PGJDBC requires this unless rs is scrollable
+				++ rows;
+		}
+
+		return new int[] { rows, cols };
 	}
 
 	/**
-	 * Predicate testing that an object is a {@code ResultSet} that has only
+	 * Equivalent to
+	 * {@link #voidResultSetDims(Object,boolean) voidResultSetDims(o,false)};
+	 */
+	public static int[] voidResultSetDims(Object o)	throws Exception
+	{
+		return voidResultSetDims(o, false);
+	}
+
+	/**
+	 * A predicate testing that an object is a {@code ResultSet} that has only
 	 * columns of {@code void} type, and the expected number of rows
 	 * and columns.
 	 *<p>
@@ -2078,7 +2401,7 @@ public static boolean isVoidResultSet(Object o, int rows, int columns)
 	/**
 	 * Executes a state machine specified in the form of
 	 * a list of lambdas representing its states, to verify that a
-	 * {@link #q(Statement,Callable) result stream} is as expected.
+	 * {@linkplain #q(Statement,Callable) result stream} is as expected.
 	 *<p>
 	 * Treats the list of lambdas as a set of consecutively-numbered states
 	 * (the first in the list is state number 1, and is the initial state).
@@ -2114,9 +2437,10 @@ public static boolean isVoidResultSet(Object o, int rows, int columns)
 	 * by {@link InvocationHandler}, an existing functional interface with a
 	 * versatile argument list and permissive {@code throws} clause. Each state
 	 * must be represented as a lambda with three parameters (the convention
-	 * {@code (o,p,q)} is suggested), of which only the first is used. If Java
-	 * ever completes the transition to {@code _} as an unused-parameter marker,
-	 * the suggested convention will be {@code (o,_,_)}.
+	 * {@code (o,p,q)} is suggested), of which only the first is normally used.
+	 * If Java ever completes the transition to {@code _} as an unused-parameter
+	 * marker, the suggested convention will be {@code (o,_,_)}, unless the
+	 * third (<var>q</var>) is also needed for special purposes (more below).
 	 *<p>
 	 * As the input item passed to each state is typed {@code Object}, and as
 	 * null can only represent the end of input, it may be common for a state to
@@ -2126,10 +2450,18 @@ public static boolean isVoidResultSet(Object o, int rows, int columns)
 	 * throw a specific instance of {@code ClassCastException}, which will be
 	 * treated, when caught by {@code stateMachine}, just as if the state
 	 * had returned {@code false}.
+	 *<p>
+	 * The third parameter to an {@code InvocationHandler} is an {@code Object}
+	 * array, and is here used to pass additional information that may at times
+	 * be of use in a state. The first element of the array holds the boxed form
+	 * of the current (1-based) state number. As a state must indicate the next
+	 * state by returning an absolute state number, having the state's own
+	 * number available opens the possibility of reusable presupplied state
+	 * implementations that do not depend on their absolute position.
 	 * @param name A name for this state machine, used only in exception
 	 * messages if it fails to match all the input
 	 * @param reporter a Consumer to accept a diagnostic string if the machine
-	 * fails to match, defaulting if null to System.err::println
+	 * fails to match, defaulting if null to {@code System.err::println}
 	 * @param input A Stream of input items, of which none may be null
 	 * @param states Lambdas representing states of the machine
 	 * @return true if an accepting state was reached coinciding with the end
@@ -2169,7 +2501,8 @@ public static boolean stateMachine(
 					hasCurrent = true;
 				}
 
-				result = invoke(states[currentState], currentInput);
+				result =
+					invoke(states[currentState], currentState, currentInput);
 
 				if ( result instanceof Boolean )
 				{
@@ -2199,7 +2532,7 @@ public static boolean stateMachine(
 			for ( ;; )
 			{
 				++ stepCount;
-				result = invoke(states[currentState], null);
+				result = invoke(states[currentState], currentState, null);
 				if ( result instanceof Boolean  &&  (Boolean)result )
 					return true;
 				else if ( result instanceof Integer  &&  0 > (Integer)result )
@@ -2237,12 +2570,21 @@ public static <T> T as(Class<T> clazz, Object o)
 	private static final ClassCastException failedAsException =
 		new ClassCastException();
 
-	private static Object invoke(InvocationHandler h, Object o)
+	/**
+	 * Invokes the state handler <var>h</var>, passing it the current object
+	 * <var>o</var> and, for special purposes, the state index (adjusted to
+	 * be 1-based).
+	 *<p>
+	 * Conforming to the existing {@code InvocationHandler} interface, the
+	 * state index is passed in boxed form as element zero of an {@code Object}
+	 * array passed as the third argument.
+	 */
+	private static Object invoke(InvocationHandler h, int stateIdx, Object o)
 	throws Exception
 	{
 		try
 		{
-			return h.invoke(o, null, null);
+			return h.invoke(o, null, new Object[] { 1 + stateIdx });
 		}
 		catch ( ClassCastException e )
 		{
@@ -2278,7 +2620,7 @@ private static Object invoke(InvocationHandler h, Object o)
 	private static final String PM_STATUS_READY = "ready   ";
 
 	/**
-	 * Wait for the {@code postmaster.pid} file to have the right contents
+	 * Waits for the {@code postmaster.pid} file to have the right contents
 	 * (the right pid for process <em>p</em>, and ready status for PG 10+).
 	 *<p>
 	 * The {code PostgresNode.pm} version of this is also used when shutting
@@ -2460,9 +2802,9 @@ && waitPrePG10() )
 	}
 
 	/**
-	 * Check whether the server being started is earlier than PG 10 and, if so,
-	 * sleep for a period expected to be adequate for it to become ready to
-	 * accept connections, then return true.
+	 * Checks whether the server being started is earlier than PG 10 and, if so,
+	 * sleeps for a period expected to be adequate for it to become ready to
+	 * accept connections, then returns true.
 	 *<p>
 	 * This is called from the generic {@code wait_for_pid_file}, only if the
 	 * file has already appeared and has all entries but {@code PM_STATUS}. That
@@ -2512,7 +2854,7 @@ private boolean waitPrePG10() throws Exception
 	 * changes there if desirable.
 	 */
 	/**
-	 * Adjust the command arguments of a {@code ProcessBuilder} so that they
+	 * Adjusts the command arguments of a {@code ProcessBuilder} so that they
 	 * will be recovered correctly on Windows by a target C/C++ program using
 	 * the argument parsing algorithm of the usual C run-time code, when it is
 	 * known that the command will not be handled first by {@code cmd}.
@@ -2692,7 +3034,7 @@ public static ProcessBuilder forWindowsCRuntime(ProcessBuilder pb)
 	}
 
 	/**
-	 * Adjust the command arguments of a {@code ProcessBuilder} that would
+	 * Adjusts the command arguments of a {@code ProcessBuilder} that would
 	 * directly invoke {@code postgres} to start a server, so that it will
 	 * instead start {@code postgres} via {@code pg_ctl}.
 	 *<p>
diff --git a/pljava-packaging/src/site/markdown/index.md b/pljava-packaging/src/site/markdown/index.md
index 8a1e332d9..1e0773a46 100644
--- a/pljava-packaging/src/site/markdown/index.md
+++ b/pljava-packaging/src/site/markdown/index.md
@@ -28,9 +28,11 @@ That allows `jshell` to serve as an environment for scripting tests
 of PL/Java in a running PostgreSQL instance, with capabilities similar to
 (and modeled on) the [PostgresNode][] Perl module distributed with PostgreSQL.
 
-See the javadoc for [the Node class][node] for details.
+See [this introduction][nodetut] and the javadoc for [the Node class][node]
+for details.
 
 [install]: ../install/install.html
 [JShell]: https://docs.oracle.com/javase/9/jshell/introduction-jshell.htm
 [PostgresNode]: https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/test/perl/PostgresNode.pm;h=aec3b9a;hb=e640093
 [node]: apidocs/org/postgresql/pljava/packaging/Node.html
+[nodetut]: ../develop/node.html
diff --git a/pljava-so/src/main/c/Backend.c b/pljava-so/src/main/c/Backend.c
index 287652fd2..9b70c28c1 100644
--- a/pljava-so/src/main/c/Backend.c
+++ b/pljava-so/src/main/c/Backend.c
@@ -23,12 +23,13 @@
 #include <fmgr.h>
 #include <access/heapam.h>
 #include <utils/syscache.h>
+#include <utils/timeout.h>
 #include <catalog/catalog.h>
 #include <catalog/pg_proc.h>
 #include <catalog/pg_type.h>
 
 #if PG_VERSION_NUM >= 120000
- #ifdef HAVE_DLOPEN
+ #if defined(HAVE_DLOPEN)  ||  PG_VERSION_NUM >= 160000 && ! defined(WIN32)
  #include <dlfcn.h>
  #endif
  #define pg_dlopen(f) dlopen((f), RTLD_NOW | RTLD_GLOBAL)
@@ -58,10 +59,6 @@
 #include "pljava/SPI.h"
 #include "pljava/type/String.h"
 
-#if PG_VERSION_NUM >= 90300
-#include "utils/timeout.h"
-#endif
-
 /* Include the 'magic block' that PostgreSQL 8.2 and up will use to ensure
  * that a module is not loaded into an incompatible server.
  */ 
@@ -250,152 +247,133 @@ static bool javaGE17 = false;
 
 static void initsequencer(enum initstage is, bool tolerant);
 
-#if PG_VERSION_NUM >= 90100
-	static bool check_libjvm_location(
-		char **newval, void **extra, GucSource source);
-	static bool check_vmoptions(
-		char **newval, void **extra, GucSource source);
-	static bool check_modulepath(
-		char **newval, void **extra, GucSource source);
-	static bool check_policy_urls(
-		char **newval, void **extra, GucSource source);
-	static bool check_enabled(
-		bool *newval, void **extra, GucSource source);
-	static bool check_java_thread_pg_entry(
-		int *newval, void **extra, GucSource source);
-
-	/* Check hooks will always allow "setting" a value that is the same as
-	 * current; otherwise, it would be frustrating to have just found settings
-	 * that work, and be unable to save them with ALTER DATABASE SET ... because
-	 * the check hook is called for that too, and would say it is too late....
-	 */
+static bool check_libjvm_location(
+	char **newval, void **extra, GucSource source);
+static bool check_vmoptions(
+	char **newval, void **extra, GucSource source);
+static bool check_modulepath(
+	char **newval, void **extra, GucSource source);
+static bool check_policy_urls(
+	char **newval, void **extra, GucSource source);
+static bool check_enabled(
+	bool *newval, void **extra, GucSource source);
+static bool check_java_thread_pg_entry(
+	int *newval, void **extra, GucSource source);
+
+/* Check hooks will always allow "setting" a value that is the same as
+ * current; otherwise, it would be frustrating to have just found settings
+ * that work, and be unable to save them with ALTER DATABASE SET ... because
+ * the check hook is called for that too, and would say it is too late....
+ */
 
-	static bool check_libjvm_location(
-		char **newval, void **extra, GucSource source)
-	{
-		if ( initstage < IS_CAND_JVMOPENED )
-			return true;
-		if ( libjvmlocation == *newval )
-			return true;
-		if ( libjvmlocation && *newval && 0 == strcmp(libjvmlocation, *newval) )
-			return true;
-		GUC_check_errmsg(
-			"too late to change \"pljava.libjvm_location\" setting");
-		GUC_check_errdetail(
-			"Changing the setting can have no effect after "
-			"PL/Java has found and opened the library it points to.");
-		GUC_check_errhint(
-			"To try a different value, exit this session and start a new one.");
-		return false;
-	}
+static bool check_libjvm_location(
+	char **newval, void **extra, GucSource source)
+{
+	if ( initstage < IS_CAND_JVMOPENED )
+		return true;
+	if ( libjvmlocation == *newval )
+		return true;
+	if ( libjvmlocation && *newval && 0 == strcmp(libjvmlocation, *newval) )
+		return true;
+	GUC_check_errmsg(
+		"too late to change \"pljava.libjvm_location\" setting");
+	GUC_check_errdetail(
+		"Changing the setting can have no effect after "
+		"PL/Java has found and opened the library it points to.");
+	GUC_check_errhint(
+		"To try a different value, exit this session and start a new one.");
+	return false;
+}
 
-	static bool check_vmoptions(
-		char **newval, void **extra, GucSource source)
-	{
-		if ( initstage < IS_JAVAVM_OPTLIST )
-			return true;
-		if ( vmoptions == *newval )
-			return true;
-		if ( vmoptions && *newval && 0 == strcmp(vmoptions, *newval) )
-			return true;
-		GUC_check_errmsg(
-			"too late to change \"pljava.vmoptions\" setting");
-		GUC_check_errdetail(
-			"Changing the setting can have no effect after "
-			"PL/Java has started the Java virtual machine.");
-		GUC_check_errhint(
-			"To try a different value, exit this session and start a new one.");
-		return false;
-	}
+static bool check_vmoptions(
+	char **newval, void **extra, GucSource source)
+{
+	if ( initstage < IS_JAVAVM_OPTLIST )
+		return true;
+	if ( vmoptions == *newval )
+		return true;
+	if ( vmoptions && *newval && 0 == strcmp(vmoptions, *newval) )
+		return true;
+	GUC_check_errmsg(
+		"too late to change \"pljava.vmoptions\" setting");
+	GUC_check_errdetail(
+		"Changing the setting can have no effect after "
+		"PL/Java has started the Java virtual machine.");
+	GUC_check_errhint(
+		"To try a different value, exit this session and start a new one.");
+	return false;
+}
 
-	static bool check_modulepath(
-		char **newval, void **extra, GucSource source)
-	{
-		if ( initstage < IS_JAVAVM_OPTLIST )
-			return true;
-		if ( modulepath == *newval )
-			return true;
-		if ( modulepath && *newval && 0 == strcmp(modulepath, *newval) )
-			return true;
-		GUC_check_errmsg(
-			"too late to change \"pljava.module_path\" setting");
-		GUC_check_errdetail(
-			"Changing the setting has no effect after "
-			"PL/Java has started the Java virtual machine.");
-		GUC_check_errhint(
-			"To try a different value, exit this session and start a new one.");
-		return false;
-	}
+static bool check_modulepath(
+	char **newval, void **extra, GucSource source)
+{
+	if ( initstage < IS_JAVAVM_OPTLIST )
+		return true;
+	if ( modulepath == *newval )
+		return true;
+	if ( modulepath && *newval && 0 == strcmp(modulepath, *newval) )
+		return true;
+	GUC_check_errmsg(
+		"too late to change \"pljava.module_path\" setting");
+	GUC_check_errdetail(
+		"Changing the setting has no effect after "
+		"PL/Java has started the Java virtual machine.");
+	GUC_check_errhint(
+		"To try a different value, exit this session and start a new one.");
+	return false;
+}
 
-	static bool check_policy_urls(
-		char **newval, void **extra, GucSource source)
-	{
-		if ( initstage < IS_JAVAVM_OPTLIST )
-			return true;
-		if ( policy_urls == *newval )
-			return true;
-		if ( policy_urls && *newval && 0 == strcmp(policy_urls, *newval) )
-			return true;
-		GUC_check_errmsg(
-			"too late to change \"pljava.policy_urls\" setting");
-		GUC_check_errdetail(
-			"Changing the setting has no effect after "
-			"PL/Java has started the Java virtual machine.");
-		GUC_check_errhint(
-			"To try a different value, exit this session and start a new one.");
-		return false;
-	}
+static bool check_policy_urls(
+	char **newval, void **extra, GucSource source)
+{
+	if ( initstage < IS_JAVAVM_OPTLIST )
+		return true;
+	if ( policy_urls == *newval )
+		return true;
+	if ( policy_urls && *newval && 0 == strcmp(policy_urls, *newval) )
+		return true;
+	GUC_check_errmsg(
+		"too late to change \"pljava.policy_urls\" setting");
+	GUC_check_errdetail(
+		"Changing the setting has no effect after "
+		"PL/Java has started the Java virtual machine.");
+	GUC_check_errhint(
+		"To try a different value, exit this session and start a new one.");
+	return false;
+}
 
-	static bool check_enabled(
-		bool *newval, void **extra, GucSource source)
-	{
-		if ( initstage < IS_PLJAVA_ENABLED )
-			return true;
-		if ( *newval )
-			return true;
-		GUC_check_errmsg(
-			"too late to change \"pljava.enable\" setting");
-		GUC_check_errdetail(
-			"Start-up has progressed past the point where it is checked.");
-		GUC_check_errhint(
-			"For another chance, exit this session and start a new one.");
-		return false;
-	}
+static bool check_enabled(
+	bool *newval, void **extra, GucSource source)
+{
+	if ( initstage < IS_PLJAVA_ENABLED )
+		return true;
+	if ( *newval )
+		return true;
+	GUC_check_errmsg(
+		"too late to change \"pljava.enable\" setting");
+	GUC_check_errdetail(
+		"Start-up has progressed past the point where it is checked.");
+	GUC_check_errhint(
+		"For another chance, exit this session and start a new one.");
+	return false;
+}
 
-	static bool check_java_thread_pg_entry(
-		int *newval, void **extra, GucSource source)
-	{
-		if ( initstage < IS_PLJAVA_FOUND )
-			return true;
-		if ( java_thread_pg_entry == *newval )
-			return true;
-		GUC_check_errmsg(
-			"too late to change \"pljava.java_thread_pg_entry\" setting");
-		GUC_check_errdetail(
-			"Start-up has progressed past the point where it is checked.");
-		GUC_check_errhint(
-			"For another chance, exit this session and start a new one.");
-		return false;
-	}
-#endif
+static bool check_java_thread_pg_entry(
+	int *newval, void **extra, GucSource source)
+{
+	if ( initstage < IS_PLJAVA_FOUND )
+		return true;
+	if ( java_thread_pg_entry == *newval )
+		return true;
+	GUC_check_errmsg(
+		"too late to change \"pljava.java_thread_pg_entry\" setting");
+	GUC_check_errdetail(
+		"Start-up has progressed past the point where it is checked.");
+	GUC_check_errhint(
+		"For another chance, exit this session and start a new one.");
+	return false;
+}
 
-#if PG_VERSION_NUM < 90100
-#define errdetail_internal errdetail
-#define ASSIGNHOOK(name,type) \
-	static bool \
-	CppConcat(assign_,name)(type newval, bool doit, GucSource source); \
-	static bool \
-	CppConcat(assign_,name)(type newval, bool doit, GucSource source)
-#define ASSIGNRETURN(thing) return (thing)
-#define ASSIGNRETURNIFCHECK(thing) if (doit) ; else return (thing)
-#define ASSIGNRETURNIFNXACT(thing) \
-	if (! deferInit && pljavaViableXact()) ; else return (thing)
-#define ASSIGNSTRINGHOOK(name) \
-	static const char * \
-	CppConcat(assign_,name)(const char *newval, bool doit, GucSource source); \
-	static const char * \
-	CppConcat(assign_,name)(const char *newval, bool doit, GucSource source)
-#else
 #define ASSIGNHOOK(name,type) \
 	static void \
 	CppConcat(assign_,name)(type newval, void *extra); \
@@ -406,7 +384,6 @@ static void initsequencer(enum initstage is, bool tolerant);
 #define ASSIGNRETURNIFNXACT(thing) \
 	if (! deferInit && pljavaViableXact()) ; else return
 #define ASSIGNSTRINGHOOK(name) ASSIGNHOOK(name, const char *)
-#endif
 
 #define ASSIGNENUMHOOK(name) ASSIGNHOOK(name,int)
 #define ENUMBOOTVAL(entry) ((entry).val)
@@ -796,18 +773,13 @@ static void initsequencer(enum initstage is, bool tolerant)
 			 * are just function parameters with evaluation order unknown.
 			 */
 			StringInfoData buf;
-#if PG_VERSION_NUM >= 90200
-#define MOREHINT \
-				appendStringInfo(&buf, \
-					"using ALTER DATABASE %s SET ... FROM CURRENT or ", \
-					pljavaDbName()),
-#else
-#define MOREHINT
-#endif
+
 			ereport(NOTICE, (
 				errmsg("PL/Java successfully started after adjusting settings"),
 				(initStringInfo(&buf),
-				MOREHINT
+				appendStringInfo(&buf, \
+					"using ALTER DATABASE %s SET ... FROM CURRENT or ", \
+					pljavaDbName()),
 				errhint("The settings that worked should be saved (%s"
 					"in the \"%s\" file). For a reminder of what has been set, "
 					"try: SELECT name, setting FROM pg_settings WHERE name LIKE"
@@ -816,7 +788,7 @@ static void initsequencer(enum initstage is, bool tolerant)
 					superuser()
 						? PG_GETCONFIGOPTION("config_file")
 						: "postgresql.conf"))));
-#undef MOREHINT
+
 			if ( loadAsExtensionFailed )
 			{
 #if PG_VERSION_NUM < 130000
@@ -902,7 +874,7 @@ static void reLogWithChangedLevel(int level)
 	else if ( ERRCODE_WARNING == category || ERRCODE_NO_DATA == category ||
 		ERRCODE_SUCCESSFUL_COMPLETION == category )
 		sqlstate = ERRCODE_INTERNAL_ERROR;
-#if PG_VERSION_NUM >= 90500
+
 	edata->elevel = level;
 	edata->sqlerrcode = sqlstate;
 	PG_TRY();
@@ -916,43 +888,6 @@ static void reLogWithChangedLevel(int level)
 	}
 	PG_END_TRY();
 	FreeErrorData(edata);
-#else
-	if (!errstart(level, edata->filename, edata->lineno,
-				  edata->funcname, NULL))
-	{
-		FreeErrorData(edata);
-		return;
-	}
-
-	errcode(sqlstate);
-	if (edata->message)
-		errmsg("%s", edata->message);
-	if (edata->detail)
-		errdetail("%s", edata->detail);
-	if (edata->detail_log)
-		errdetail_log("%s", edata->detail_log);
-	if (edata->hint)
-		errhint("%s", edata->hint);
-	if (edata->context)
-		errcontext("%s", edata->context); /* this may need to be trimmed */
-#if PG_VERSION_NUM >= 90300
-	if (edata->schema_name)
-		err_generic_string(PG_DIAG_SCHEMA_NAME, edata->schema_name);
-	if (edata->table_name)
-		err_generic_string(PG_DIAG_TABLE_NAME, edata->table_name);
-	if (edata->column_name)
-		err_generic_string(PG_DIAG_COLUMN_NAME, edata->column_name);
-	if (edata->datatype_name)
-		err_generic_string(PG_DIAG_DATATYPE_NAME, edata->datatype_name);
-	if (edata->constraint_name)
-		err_generic_string(PG_DIAG_CONSTRAINT_NAME, edata->constraint_name);
-#endif
-	if (edata->internalquery)
-		internalerrquery(edata->internalquery);
-
-	FreeErrorData(edata);
-	errfinish(0);
-#endif
 }
 
 void _PG_init()
@@ -969,8 +904,7 @@ void _PG_init()
 	 * preparing the launch options before it is launched. PostgreSQL knows what
 	 * it is, but won't directly say; give it some choices and it'll pick one.
 	 * Alternatively, let Maven or Ant determine and add a -D at build time from
-	 * the path.separator property. Maybe that's cleaner? This only works for
-	 * PG_VERSION_NUM >= 90100.
+	 * the path.separator property. Maybe that's cleaner?
 	 */
 	sep = first_path_var_separator(":;");
 	if ( NULL == sep )
@@ -1340,12 +1274,7 @@ static void pljavaQuickDieHandler(int signum)
 }
 
 static sigjmp_buf recoverBuf;
-static void terminationTimeoutHandler(
-#if PG_VERSION_NUM >= 90300
-#else
-	int signum
-#endif
-)
+static void terminationTimeoutHandler()
 {
 	kill(MyProcPid, SIGQUIT);
 	
@@ -1387,12 +1316,7 @@ static void _destroyJavaVM(int status, Datum dummy)
 	{
 		Invocation ctx;
 #ifdef USE_PLJAVA_SIGHANDLERS
-
-#if PG_VERSION_NUM >= 90300
 		TimeoutId tid;
-#else
-		pqsigfunc saveSigAlrm;
-#endif
 
 		Invocation_pushBootContext(&ctx);
 		if(sigsetjmp(recoverBuf, 1) != 0)
@@ -1404,24 +1328,13 @@ static void _destroyJavaVM(int status, Datum dummy)
 			return;
 		}
 
-#if PG_VERSION_NUM >= 90300
 		tid = RegisterTimeout(USER_TIMEOUT, terminationTimeoutHandler);
 		enable_timeout_after(tid, 5000);
-#else
-		saveSigAlrm = pqsignal(SIGALRM, terminationTimeoutHandler);
-		enable_sig_alarm(5000, false);
-#endif
 
 		elog(DEBUG2, "shutting down the Java virtual machine");
 		JNI_destroyVM(s_javaVM);
 
-#if PG_VERSION_NUM >= 90300
 		disable_timeout(tid, false);
-#else
-		disable_sig_alarm(false);
-		pqsignal(SIGALRM, saveSigAlrm);
-#endif
-
 #else
 		Invocation_pushBootContext(&ctx);
 		elog(DEBUG2, "shutting down the Java virtual machine");
@@ -1646,12 +1559,7 @@ static jint initializeJavaVM(JVMOptList *optList)
 #define GUCBOOTVAL(v) (v),
 #define GUCBOOTASSIGN(a, v)
 #define GUCFLAGS(f) (f),
-
-#if PG_VERSION_NUM >= 90100
 #define GUCCHECK(h) (h),
-#else
-#define GUCCHECK(h)
-#endif
 
 #define BOOL_GUC(name, short_desc, long_desc, valueAddr, bootValue, context, \
                  flags, check_hook, assign_hook, show_hook) \
@@ -1685,11 +1593,7 @@ static jint initializeJavaVM(JVMOptList *optList)
 #define PLJAVA_LIBJVMDEFAULT "libjvm"
 #endif
 
-#if PG_VERSION_NUM >= 90200
 #define PLJAVA_ENABLE_DEFAULT true
-#else
-#define PLJAVA_ENABLE_DEFAULT false
-#endif
 
 #if PG_VERSION_NUM < 110000
 #define PLJAVA_IMPLEMENTOR_FLAGS GUC_LIST_INPUT | GUC_LIST_QUOTE
diff --git a/pljava-so/src/main/c/DualState.c b/pljava-so/src/main/c/DualState.c
index e557231e5..17d32ab21 100644
--- a/pljava-so/src/main/c/DualState.c
+++ b/pljava-so/src/main/c/DualState.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2019 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -44,10 +44,6 @@ extern void pljava_ExecutionPlan_initialize(void);
 #include "pljava/SQLInputFromTuple.h"
 #include "pljava/VarlenaWrapper.h"
 
-#if PG_VERSION_NUM < 80400
-#include <access/heapam.h> /* heap_freetuple was there then */
-#endif
-
 static jclass s_DualState_class;
 
 static jmethodID s_DualState_resourceOwnerRelease;
diff --git a/pljava-so/src/main/c/Exception.c b/pljava-so/src/main/c/Exception.c
index 071b8cf49..ccac4e7b8 100644
--- a/pljava-so/src/main/c/Exception.c
+++ b/pljava-so/src/main/c/Exception.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -59,7 +59,13 @@ Exception_featureNotSupported(const char* requestedFeature, const char* introVer
 		appendStringInfoString(&buf, requestedFeature);
 		appendStringInfoString(&buf, " lacks support in PostgreSQL version ");
 		appendStringInfo(&buf, "%d.%d",
-						PG_VERSION_NUM / 10000, (PG_VERSION_NUM / 100) % 100);
+						PG_VERSION_NUM / 10000,
+#if PG_VERSION_NUM >= 100000
+						(PG_VERSION_NUM) % 10000
+#else
+						(PG_VERSION_NUM / 100) % 100
+#endif
+		);
 		appendStringInfoString(&buf, ". It was introduced in version ");
 		appendStringInfoString(&buf, introVersion);
 	
diff --git a/pljava-so/src/main/c/ExecutionPlan.c b/pljava-so/src/main/c/ExecutionPlan.c
index 6ff53eb49..ed39bc0fe 100644
--- a/pljava-so/src/main/c/ExecutionPlan.c
+++ b/pljava-so/src/main/c/ExecutionPlan.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2019 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -278,9 +278,7 @@ JNIEXPORT jobject JNICALL
 Java_org_postgresql_pljava_internal_ExecutionPlan__1prepare(JNIEnv* env, jclass clazz, jobject key, jstring jcmd, jobjectArray paramTypes)
 {
 	jobject result = 0;
-#if PG_VERSION_NUM >= 90200
 	int spi_ret;
-#endif
 	BEGIN_NATIVE
 	STACK_BASE_VARS
 	STACK_BASE_PUSH(env)
@@ -321,16 +319,12 @@ Java_org_postgresql_pljava_internal_ExecutionPlan__1prepare(JNIEnv* env, jclass
 			/* Make the plan durable
 			 */
 			p2l.longVal = 0L; /* ensure that the rest is zeroed out */
-#if PG_VERSION_NUM >= 90200
 			spi_ret = SPI_keepplan(ePlan);
 			if ( 0 == spi_ret )
 				p2l.ptrVal = ePlan;
 			else
 				Exception_throwSPI("keepplan", spi_ret);
-#else
-			p2l.ptrVal = SPI_saveplan(ePlan);
-			SPI_freeplan(ePlan); /* Get rid of original, nobody can see it */
-#endif
+
 			result = JNI_newObjectLocked(
 				s_ExecutionPlan_class, s_ExecutionPlan_init,
 				/* (jlong)0 as resource owner: the saved plan isn't transient */
diff --git a/pljava-so/src/main/c/Function.c b/pljava-so/src/main/c/Function.c
index a46c0e6dd..249374271 100644
--- a/pljava-so/src/main/c/Function.c
+++ b/pljava-so/src/main/c/Function.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2022 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -34,6 +34,10 @@
 #include <funcapi.h>
 #include <utils/typcache.h>
 
+#if PG_VERSION_NUM >= 160000
+#define PG_FUNCNAME_MACRO __func__
+#endif
+
 #ifdef _MSC_VER
 #	define strcasecmp _stricmp
 #	define strncasecmp _strnicmp
@@ -41,15 +45,6 @@
 
 #define PARAM_OIDS(procStruct) (procStruct)->proargtypes.values
 
-#if 90305<=PG_VERSION_NUM || \
-	90209<=PG_VERSION_NUM && PG_VERSION_NUM<90300 || \
-	90114<=PG_VERSION_NUM && PG_VERSION_NUM<90200 || \
-	90018<=PG_VERSION_NUM && PG_VERSION_NUM<90100 || \
-	80422<=PG_VERSION_NUM && PG_VERSION_NUM<90000
-#else
-#error "Need fallback for heap_copy_tuple_as_datum"
-#endif
-
 #define COUNTCHECK(refs, prims) ((jshort)(((refs) << 8) | ((prims) & 0xff)))
 
 jobject pljava_Function_NO_LOADER;
diff --git a/pljava-so/src/main/c/InstallHelper.c b/pljava-so/src/main/c/InstallHelper.c
index 30af880ae..2cb5a9cb3 100644
--- a/pljava-so/src/main/c/InstallHelper.c
+++ b/pljava-so/src/main/c/InstallHelper.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2015-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -10,17 +10,11 @@
  *   Chapman Flack
  */
 #include <postgres.h>
-#if PG_VERSION_NUM >= 90300
 #include <access/htup_details.h>
-#else
-#include <access/htup.h>
-#endif
 #include <access/xact.h>
 #include <catalog/pg_language.h>
 #include <catalog/pg_proc.h>
-#if PG_VERSION_NUM >= 90100
 #include <commands/extension.h>
-#endif
 #include <commands/portalcmds.h>
 #include <executor/spi.h>
 #include <miscadmin.h>
@@ -30,20 +24,15 @@
 #include <utils/builtins.h>
 #include <utils/lsyscache.h>
 #include <utils/memutils.h>
-#if PG_VERSION_NUM >= 80400
 #include <utils/snapmgr.h>
-#endif
 #include <utils/syscache.h>
 
 #if PG_VERSION_NUM >= 120000
 #include <catalog/pg_namespace.h>
 #define GetNamespaceOid(k1) \
 	GetSysCacheOid1(NAMESPACENAME, Anum_pg_namespace_oid, k1)
-#elif PG_VERSION_NUM >= 90000
-#define GetNamespaceOid(k1) GetSysCacheOid1(NAMESPACENAME, k1)
 #else
-#define SearchSysCache1(cid, k1) SearchSysCache(cid, k1, 0, 0, 0)
-#define GetNamespaceOid(k1) GetSysCacheOid(NAMESPACENAME, k1, 0, 0, 0)
+#define GetNamespaceOid(k1) GetSysCacheOid1(NAMESPACENAME, k1)
 #endif
 
 #include "pljava/InstallHelper.h"
@@ -55,47 +44,17 @@
 #include "pljava/type/String.h"
 
 /*
- * Before 9.1, there was no creating_extension. Before 9.5, it did not have
- * PGDLLIMPORT and so was not visible in Windows. In either case, just define
- * it to be false, but also define CREATING_EXTENSION_HACK if on Windows and
- * it needs to be tested for in some roundabout way.
- */
-#if PG_VERSION_NUM < 90100 || defined(_MSC_VER) && PG_VERSION_NUM < 90500
-#define creating_extension false
-#if PG_VERSION_NUM >= 90100
-#define CREATING_EXTENSION_HACK
-#endif
-#endif
-
-/*
- * Before 9.1, there was no IsBinaryUpgrade. Before 9.5, it did not have
- * PGDLLIMPORT and so was not visible in Windows. In either case, just define
- * it to be false; Windows users may have trouble using pg_upgrade to versions
- * earlier than 9.5, but with the current version being 9.6 that should be rare.
- */
-#if PG_VERSION_NUM < 90100 || defined(_MSC_VER) && PG_VERSION_NUM < 90500
-#define IsBinaryUpgrade false
-#endif
-
-/*
- * Before 9.3, there was no IsBackgroundWorker. As of 9.6.1 it still does not
+ * As of 9.6.1, IsBackgroundWorker still does not
  * have PGDLLIMPORT, but MyBgworkerEntry != NULL can be used in MSVC instead.
- * However, until 9.3.3, even that did not have PGDLLIMPORT, and there's not
- * much to be done about it. BackgroundWorkerness won't be detected in MSVC
- * for 9.3.0 through 9.3.2.
  *
  * One thing it's needed for is to avoid dereferencing MyProcPort in a
  * background worker, where it's not set.
  */
-#if PG_VERSION_NUM < 90300  ||  defined(_MSC_VER) && PG_VERSION_NUM < 90303
-#define IsBackgroundWorker false
-#else
 #include <commands/dbcommands.h>
 #if defined(_MSC_VER)
 #include <postmaster/bgworker.h>
 #define IsBackgroundWorker (MyBgworkerEntry != NULL)
 #endif
-#endif
 
 /*
  * The name of the table the extension scripts will create to pass information
@@ -112,7 +71,7 @@ static jfieldID  s_InstallHelper_MANAGE_CONTEXT_LOADER;
 
 static bool extensionExNihilo = false;
 
-static void checkLoadPath( bool *livecheck);
+static void checkLoadPath(void);
 static void getExtensionLoadPath(void);
 static char *origUserName();
 
@@ -153,7 +112,6 @@ static char *origUserName()
 {
 	if ( IsAutoVacuumWorkerProcess() || IsBackgroundWorker )
 	{
-#if PG_VERSION_NUM >= 90500
 		char *shortlived;
 		static char *longlived;
 		if ( NULL == longlived )
@@ -163,14 +121,6 @@ static char *origUserName()
 			pfree(shortlived);
 		}
 		return longlived;
-#else
-		ereport(ERROR, (
-			errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			errmsg("PL/Java in a background or autovacuum worker not supported "
-				"in this PostgreSQL version"),
-			errhint("PostgreSQL 9.5 is the first version in which "
-				"such usage is supported.")));
-#endif
 	}
 	return MyProcPort->user_name;
 }
@@ -178,22 +128,17 @@ static char *origUserName()
 char const *pljavaClusterName()
 {
 	/*
-	 * If PostgreSQL isn't at least 9.5, there can't BE a cluster name, and if
-	 * it is, then there's always one (even if it is an empty string), so
-	 * PG_GETCONFIGOPTION is safe.
+	 * In PostgreSQL of at least 9.5, there's always one (even if it is an empty
+	 * string), so PG_GETCONFIGOPTION is safe.
 	 */
-#if PG_VERSION_NUM < 90500
-	return "";
-#else
 	return PG_GETCONFIGOPTION("cluster_name");
-#endif
 }
 
 void pljavaCheckExtension( bool *livecheck)
 {
 	if ( ! creating_extension )
 	{
-		checkLoadPath( livecheck);
+		checkLoadPath();
 		return;
 	}
 	if ( NULL != livecheck )
@@ -216,29 +161,17 @@ void pljavaCheckExtension( bool *livecheck)
  * on Windows. So if livecheck isn't null, this function only needs to proceed
  * as far as the CREATING_EXTENSION_HACK and then return.
  */
-static void checkLoadPath( bool *livecheck)
+static void checkLoadPath()
 {
 	List *l;
 	Node *ut;
 	LoadStmt *ls;
-#if PG_VERSION_NUM >= 80300
 	PlannedStmt *ps;
-#else
-	Query *ps;
-#endif
 
-#ifndef CREATING_EXTENSION_HACK
-	if ( NULL != livecheck )
-		return;
-#endif
 	if ( NULL == ActivePortal )
 		return;
-	l = ActivePortal->
-#if PG_VERSION_NUM >= 80300
-		stmts;
-#else
-		parseTrees;
-#endif
+	l = ActivePortal->stmts;
+
 	if ( NULL == l )
 		return;
 	if ( 1 < list_length( l) )
@@ -249,15 +182,10 @@ static void checkLoadPath( bool *livecheck)
 		elog(DEBUG2, "got null for first statement from ActivePortal");
 		return;
 	}
-#if PG_VERSION_NUM >= 80300
+
 	if ( T_PlannedStmt == nodeTag(ut) )
 	{
 		ps = (PlannedStmt *)ut;
-#else
-	if ( T_Query == nodeTag(ut) )
-	{
-		ps = (Query *)ut;
-#endif
 		if ( CMD_UTILITY != ps->commandType )
 		{
 			elog(DEBUG2, "ActivePortal has PlannedStmt command type %u",
@@ -272,22 +200,8 @@ static void checkLoadPath( bool *livecheck)
 		}
 	}
 	if ( T_LoadStmt != nodeTag(ut) )
-#ifdef CREATING_EXTENSION_HACK
-		if ( T_CreateExtensionStmt == nodeTag(ut) )
-		{
-			if ( NULL != livecheck )
-			{
-				*livecheck = true;
-				return;
-			}
-			getExtensionLoadPath();
-			if ( NULL != pljavaLoadPath )
-				pljavaLoadingAsExtension = true;
-		}
-#endif
-		return;
-	if ( NULL != livecheck )
 		return;
+
 	ls = (LoadStmt *)ut;
 	if ( NULL == ls->filename )
 	{
@@ -555,14 +469,9 @@ char *InstallHelper_hello()
 	nativeVer = String_createJavaStringFromNTS(SO_VERSION_STRING);
 	serverBuiltVer = String_createJavaStringFromNTS(PG_VERSION_STR);
 
-#if PG_VERSION_NUM >= 90100
 	InitFunctionCallInfoData(fcinfo, NULL, 0,
 	InvalidOid, /* collation */
 	NULL, NULL);
-#else
-	InitFunctionCallInfoData(fcinfo, NULL, 0,
-	NULL, NULL);
-#endif
 	runningVer = DatumGetTextP(pgsql_version(&fcinfo));
 	serverRunningVer = String_createJavaString(runningVer);
 	pfree(runningVer);
@@ -614,15 +523,9 @@ void InstallHelper_groundwork()
 	bool snapshot_set = false;
 	Invocation_pushInvocation(&ctx);
 	ctx.function = Function_INIT_WRITER;
-#if PG_VERSION_NUM >= 80400
 	if ( ! ActiveSnapshotSet() )
 	{
 		PushActiveSnapshot(GetTransactionSnapshot());
-#else
-	if ( NULL == ActiveSnapshot )
-	{
-		ActiveSnapshot = CopySnapshot(GetTransactionSnapshot());
-#endif
 		snapshot_set = true;
 	}
 	PG_TRY();
@@ -644,11 +547,7 @@ void InstallHelper_groundwork()
 		JNI_deleteLocalRef(jlptq);
 		if ( snapshot_set )
 		{
-#if PG_VERSION_NUM >= 80400
 			PopActiveSnapshot();
-#else
-			ActiveSnapshot = NULL;
-#endif
 		}
 		Invocation_popInvocation(false);
 	}
@@ -656,11 +555,7 @@ void InstallHelper_groundwork()
 	{
 		if ( snapshot_set )
 		{
-#if PG_VERSION_NUM >= 80400
 			PopActiveSnapshot();
-#else
-			ActiveSnapshot = NULL;
-#endif
 		}
 		Invocation_popInvocation(true);
 		PG_RE_THROW();
diff --git a/pljava-so/src/main/c/PgObject.c b/pljava-so/src/main/c/PgObject.c
index c34159323..fbf311fc7 100644
--- a/pljava-so/src/main/c/PgObject.c
+++ b/pljava-so/src/main/c/PgObject.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -66,11 +66,6 @@ const char* PgObjectClass_getName(PgObjectClass self)
 	return self->name;
 }
 
-void _PgObject_pureVirtualCalled(PgObject object)
-{
-	ereport(ERROR, (errmsg("Pure virtual method called")));
-}
-
 char* PgObject_getClassName(jclass cls)
 {
 	jstring jstr;
diff --git a/pljava-so/src/main/c/SPI.c b/pljava-so/src/main/c/SPI.c
index ea104bd9f..3d891b30d 100644
--- a/pljava-so/src/main/c/SPI.c
+++ b/pljava-so/src/main/c/SPI.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2019 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -94,14 +94,19 @@ void SPI_initialize(void)
 	CONFIRMCONST(SPI_OK_INSERT_RETURNING);
 	CONFIRMCONST(SPI_OK_DELETE_RETURNING);
 	CONFIRMCONST(SPI_OK_UPDATE_RETURNING);
-#if PG_VERSION_NUM >= 80400
 	CONFIRMCONST(SPI_OK_REWRITTEN);
-#endif
 #if PG_VERSION_NUM >= 100000
 	CONFIRMCONST(SPI_OK_REL_REGISTER);
 	CONFIRMCONST(SPI_OK_REL_UNREGISTER);
 	CONFIRMCONST(SPI_OK_TD_REGISTER);
 #endif
+#if PG_VERSION_NUM >= 150000
+	CONFIRMCONST(SPI_OK_MERGE);
+#endif
+
+#if PG_VERSION_NUM >= 110000
+	CONFIRMCONST(SPI_OPT_NONATOMIC);
+#endif
 }
 
 /****************************************
diff --git a/pljava-so/src/main/c/Session.c b/pljava-so/src/main/c/Session.c
index be4a2ccab..f551cb5b7 100644
--- a/pljava-so/src/main/c/Session.c
+++ b/pljava-so/src/main/c/Session.c
@@ -1,10 +1,14 @@
 /*
- * Copyright (c) 2004, 2005, 2006 TADA AB - Taby Sweden
- * Distributed under the terms shown in the file COPYRIGHT
- * found in the root folder of this project or at
- * http://eng.tada.se/osprojects/COPYRIGHT.html
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
- * @author Thomas Hallgren
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the The BSD 3-Clause License
+ * which accompanies this distribution, and is available at
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Contributors:
+ *   Tada AB
+ *   Chapman Flack
  */
 #include <postgres.h>
 #include <miscadmin.h>
@@ -45,9 +49,6 @@ Java_org_postgresql_pljava_internal_Session__1setUser(
 	 * a finally block after an exception.
 	 */
 	BEGIN_NATIVE_NO_ERRCHECK
-#if 80402<=PG_VERSION_NUM || \
-	80309<=PG_VERSION_NUM && PG_VERSION_NUM<80400 || \
-	80215<=PG_VERSION_NUM && PG_VERSION_NUM<80300
 	if (InSecurityRestrictedOperation())
 		ereport(ERROR,	(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg(
 			"cannot set parameter \"%s\" within security-restricted operation",
@@ -59,15 +60,6 @@ Java_org_postgresql_pljava_internal_Session__1setUser(
 	else
 		secContext &= ~SECURITY_LOCAL_USERID_CHANGE;
 	SetUserIdAndSecContext(AclId_getAclId(aclId), secContext);
-#elif PG_VERSION_NUM>=80206
-	(void)secContext; /* away with your unused-variable warnings! */
-	GetUserIdAndContext(&dummy, &wasLocalChange);
-	SetUserIdAndContext(AclId_getAclId(aclId), (bool)isLocalChange);
-#else
-	(void)secContext;
-	(void)dummy;
-	SetUserId(AclId_getAclId(aclId));
-#endif
 	END_NATIVE
 	return wasLocalChange ? JNI_TRUE : JNI_FALSE;
 }
diff --git a/pljava-so/src/main/c/TypeOid.c b/pljava-so/src/main/c/TypeOid.c
index 0fce9ad17..810053268 100644
--- a/pljava-so/src/main/c/TypeOid.c
+++ b/pljava-so/src/main/c/TypeOid.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2019-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -50,10 +50,6 @@ JNIEXPORT void JNICALL Java_org_postgresql_pljava_jdbc_TypeOid__1dummy(JNIEnv *
 	CONFIRMCONST(VARCHAROID);
 	CONFIRMCONST(OIDOID);
 	CONFIRMCONST(BPCHAROID);
-
-#if PG_VERSION_NUM >= 90100
 	CONFIRMCONST(PG_NODE_TREEOID);
-#endif
-
 	CONFIRMCONST(TRIGGEROID);
 }
diff --git a/pljava-so/src/main/c/VarlenaWrapper.c b/pljava-so/src/main/c/VarlenaWrapper.c
index 5805ace13..cb1d9e7a5 100644
--- a/pljava-so/src/main/c/VarlenaWrapper.c
+++ b/pljava-so/src/main/c/VarlenaWrapper.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -21,13 +21,8 @@
 #endif
 
 #include <utils/datum.h>
-
-#if PG_VERSION_NUM < 80400
-#define RegisterSnapshotOnOwner(s,o) NULL
-#else
 #include <utils/snapshot.h>
 #include <utils/snapmgr.h>
-#endif
 
 #include "org_postgresql_pljava_internal_VarlenaWrapper_Input_State.h"
 #include "org_postgresql_pljava_internal_VarlenaWrapper_Output_State.h"
@@ -41,37 +36,7 @@
 #define GetOldestSnapshot() NULL
 #endif
 
-#if PG_VERSION_NUM < 90400
-/*
- * There aren't 'indirect' varlenas yet, IS_EXTERNAL_ONDISK is just IS_EXTERNAL,
- * and VARATT_EXTERNAL_GET_POINTER is private inside tuptoaster.c; copy it here.
- */
-#define VARATT_IS_EXTERNAL_ONDISK VARATT_IS_EXTERNAL
-#define VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr) \
-do { \
-	varattrib_1b_e *attre = (varattrib_1b_e *) (attr); \
-	memcpy(&(toast_pointer), VARDATA_EXTERNAL(attre), sizeof(toast_pointer)); \
-} while (0)
-#endif
-
-#if PG_VERSION_NUM < 80300
-#define VARSIZE_ANY(PTR) VARSIZE(PTR)
-#define VARSIZE_ANY_EXHDR(PTR) (VARSIZE(PTR) - VARHDRSZ)
-#define SET_VARSIZE(PTR, len) VARATT_SIZEP(PTR) = len & VARATT_MASK_SIZE
-struct varatt_external
-{
-	int32 va_extsize; /* the only piece used here */
-};
-#undef VARATT_EXTERNAL_GET_POINTER
-#define VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr) \
-do { \
-	(toast_pointer).va_extsize = \
-		((varattrib *)(attr))->va_content.va_external.va_extsize; \
-} while (0)
-#define _VL_TYPE varattrib *
-#else
 #define _VL_TYPE struct varlena *
-#endif
 
 #if PG_VERSION_NUM < 140000
 #define VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) ((toast_pointer).va_extsize)
@@ -102,37 +67,6 @@ static jfieldID  s_VarlenaWrapper_Input_State_varlena;
  * final reallocation and copy will happen.
  */
 
-#if PG_VERSION_NUM < 90500
-/*
- * There aren't 'expanded' varlenas yet. Copy some defs (in simplified form)
- * and pretend there are.
- */
-typedef struct ExpandedObjectHeader ExpandedObjectHeader;
-
-typedef Size (*EOM_get_flat_size_method) (ExpandedObjectHeader *eohptr);
-typedef void (*EOM_flatten_into_method) (ExpandedObjectHeader *eohptr,
-										  void *result, Size allocated_size);
-
-typedef struct ExpandedObjectMethods
-{
-	EOM_get_flat_size_method get_flat_size;
-	EOM_flatten_into_method flatten_into;
-} ExpandedObjectMethods;
-
-struct ExpandedObjectHeader
-{
-	int32 magic;
-	MemoryContext eoh_context;
-};
-
-#define EOH_init_header(eohptr, methods, obj_context) \
-	do {(eohptr)->magic = -1; (eohptr)->eoh_context = (obj_context);} while (0)
-
-#define EOHPGetRWDatum(eohptr) (eohptr)
-#define DatumGetEOHP(d) (d)
-#define VARATT_IS_EXTERNAL_EXPANDED(attr) false
-#endif
-
 static Size VOS_get_flat_size(ExpandedObjectHeader *eohptr);
 static void VOS_flatten_into(ExpandedObjectHeader *eohptr,
 		void *result, Size allocated_size);
@@ -189,7 +123,6 @@ jobject pljava_VarlenaWrapper_Input(
 
 	vl = (_VL_TYPE) DatumGetPointer(d);
 
-#if PG_VERSION_NUM >= 90400
 	if ( VARATT_IS_EXTERNAL_INDIRECT(vl) ) /* at most once; can't be nested */
 	{
 		struct varatt_indirect redirect;
@@ -197,7 +130,6 @@ jobject pljava_VarlenaWrapper_Input(
 		vl = (_VL_TYPE)redirect.pointer;
 		d = PointerGetDatum(vl);
 	}
-#endif
 
 	parked = VARSIZE_ANY(vl);
 	actual = toast_raw_datum_size(d) - VARHDRSZ;
@@ -342,25 +274,11 @@ jobject pljava_VarlenaWrapper_Output(MemoryContext parent, ResourceOwner ro)
 Datum pljava_VarlenaWrapper_adopt(jobject vlw)
 {
 	Ptr2Long p2l;
-#if PG_VERSION_NUM < 90500
-	ExpandedObjectHeader *eohptr;
-	Size final_size;
-	void *final_result;
-#endif
 
 	p2l.longVal = JNI_callLongMethodLocked(vlw, s_VarlenaWrapper_adopt,
 					pljava_DualState_key());
-#if PG_VERSION_NUM >= 90500
+
 	return PointerGetDatum(p2l.ptrVal);
-#else
-	eohptr = p2l.ptrVal;
-	if ( -1 != eohptr->magic )
-		return PointerGetDatum(eohptr);
-	final_size = VOS_get_flat_size(eohptr);
-	final_result = MemoryContextAlloc(eohptr->eoh_context, final_size);
-	VOS_flatten_into(eohptr, final_result, final_size);
-	return PointerGetDatum(final_result);
-#endif
 }
 
 static Size VOS_get_flat_size(ExpandedObjectHeader *eohptr)
@@ -376,9 +294,6 @@ static void VOS_flatten_into(ExpandedObjectHeader *eohptr,
 	ExpandedVarlenaOutputStreamHeader *evosh =
 		(ExpandedVarlenaOutputStreamHeader *)eohptr;
 	ExpandedVarlenaOutputStreamNode *node = evosh->tail;
-#if PG_VERSION_NUM < 90500
-	ExpandedVarlenaOutputStreamNode *next;
-#endif
 
 	Assert(allocated_size == evosh->total_size);
 	SET_VARSIZE(result, allocated_size);
@@ -391,25 +306,6 @@ static void VOS_flatten_into(ExpandedObjectHeader *eohptr,
 		result = (char *)result + node->size;
 	}
 	while ( node != evosh->tail );
-
-#if PG_VERSION_NUM < 90500
-	/*
-	 * It's been flattened into the same context; the original nodes can be
-	 * freed so the 2x memory usage doesn't last longer than necessary. Freeing
-	 * them retail isn't ideal, but this is back-compatibility code. Remember
-	 * the first one wasn't a separate allocation.
-	 */
-	 node = node->next; /* this is the head, the one that can't be pfreed */
-	 evosh->tail = node; /* tail is now head, the non-pfreeable node */
-	 node = node->next;
-	 while ( node != evosh->tail )
-	 {
-		next = node->next;
-		pfree(node);
-		node = next;
-	 }
-	 pfree(evosh);
-#endif
 }
 
 void pljava_VarlenaWrapper_initialize(void)
@@ -495,7 +391,6 @@ JNIEXPORT void JNICALL
 Java_org_postgresql_pljava_internal_VarlenaWrapper_00024Input_00024State__1unregisterSnapshot
   (JNIEnv *env, jobject _this, jlong snapshot, jlong ro)
 {
-#if PG_VERSION_NUM >= 80400
 	BEGIN_NATIVE_NO_ERRCHECK
 	Ptr2Long p2lsnap;
 	Ptr2Long p2lro;
@@ -503,7 +398,6 @@ Java_org_postgresql_pljava_internal_VarlenaWrapper_00024Input_00024State__1unreg
 	p2lro.longVal = ro;
 	UnregisterSnapshotFromOwner(p2lsnap.ptrVal, p2lro.ptrVal);
 	END_NATIVE
-#endif
 }
 
 /*
@@ -517,10 +411,8 @@ Java_org_postgresql_pljava_internal_VarlenaWrapper_00024Input_00024State__1detoa
 {
 	Ptr2Long p2lvl;
 	Ptr2Long p2lcxt;
-#if PG_VERSION_NUM >= 80400
 	Ptr2Long p2lsnap;
 	Ptr2Long p2lro;
-#endif
 	Ptr2Long p2ldetoasted;
 	_VL_TYPE detoasted;
 	MemoryContext prevcxt;
@@ -530,10 +422,8 @@ Java_org_postgresql_pljava_internal_VarlenaWrapper_00024Input_00024State__1detoa
 
 	p2lvl.longVal = vl;
 	p2lcxt.longVal = cxt;
-#if PG_VERSION_NUM >= 80400
 	p2lsnap.longVal = snap;
 	p2lro.longVal = resOwner;
-#endif
 
 	prevcxt = MemoryContextSwitchTo((MemoryContext)p2lcxt.ptrVal);
 
@@ -547,10 +437,8 @@ Java_org_postgresql_pljava_internal_VarlenaWrapper_00024Input_00024State__1detoa
 		s_VarlenaWrapper_Input_State_varlena, p2ldetoasted.longVal);
 	pfree(p2lvl.ptrVal);
 
-#if PG_VERSION_NUM >= 80400
 	if ( 0 != snap )
 		UnregisterSnapshotFromOwner(p2lsnap.ptrVal, p2lro.ptrVal);
-#endif
 
 	dbb = JNI_newDirectByteBuffer(
 		VARDATA(detoasted), VARSIZE_ANY_EXHDR(detoasted));
diff --git a/pljava-so/src/main/c/XactListener.c b/pljava-so/src/main/c/XactListener.c
index 543c2cd46..096326184 100644
--- a/pljava-so/src/main/c/XactListener.c
+++ b/pljava-so/src/main/c/XactListener.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -41,11 +41,9 @@ case XACT_EVENT_##c: \
 		CASE( PREPARE );
 		CASE( PRE_COMMIT );
 		CASE( PRE_PREPARE );
-#if PG_VERSION_NUM >= 90500
 		CASE( PARALLEL_COMMIT );
 		CASE( PARALLEL_ABORT );
 		CASE( PARALLEL_PRE_COMMIT );
-#endif
 	}
 
 	JNI_callStaticVoidMethod(s_XactListener_class,
diff --git a/pljava-so/src/main/c/type/AclId.c b/pljava-so/src/main/c/type/AclId.c
index 504b8cf6a..723543bc4 100644
--- a/pljava-so/src/main/c/type/AclId.c
+++ b/pljava-so/src/main/c/type/AclId.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2019 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -22,6 +22,12 @@
 #include "org_postgresql_pljava_internal_AclId.h"
 #include "pljava/Exception.h"
 
+#if PG_VERSION_NUM >= 160000
+#include <catalog/pg_namespace.h>
+#define pg_namespace_aclcheck(oid,rid,mode) \
+	object_aclcheck(NamespaceRelationId, (oid), (rid), (mode))
+#endif
+
 static jclass    s_AclId_class;
 static jmethodID s_AclId_init;
 static jfieldID  s_AclId_m_native;
@@ -184,11 +190,7 @@ Java_org_postgresql_pljava_internal_AclId__1getName(JNIEnv* env, jobject aclId)
 	{
 		result = String_createJavaStringFromNTS(
 			GetUserNameFromId(
-#if PG_VERSION_NUM >= 90500
 				AclId_getAclId(aclId), /* noerr= */ false
-#else
-				AclId_getAclId(aclId)
-#endif
 			)
 		);
 	}
diff --git a/pljava-so/src/main/c/type/Array.c b/pljava-so/src/main/c/type/Array.c
index 232fc05aa..b2e654482 100644
--- a/pljava-so/src/main/c/type/Array.c
+++ b/pljava-so/src/main/c/type/Array.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2020 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -51,11 +51,7 @@ ArrayType* createArrayType(jsize nElems, size_t elemSize, Oid elemType, bool wit
 	v->dataoffset = (int32)dataoffset;
 	MemoryContextSwitchTo(currCtx);
 
-#if PG_VERSION_NUM < 80300
-	ARR_SIZE(v) = nBytes;
-#else
 	SET_VARSIZE(v, nBytes);
-#endif
 	ARR_NDIM(v) = 1;
 	ARR_ELEMTYPE(v) = elemType;
 	*((int*)ARR_DIMS(v)) = nElems;
@@ -88,14 +84,8 @@ static jvalue _Array_coerceDatum(Type self, Datum arg)
 			JNI_setObjectArrayElement(objArray, idx, obj.l);
 			JNI_deleteLocalRef(obj.l);
 
-#if PG_VERSION_NUM < 80300
-			values = att_addlength(values, elemLength, PointerGetDatum(values));
-			values = (char*)att_align(values, elemAlign);
-#else
 			values = att_addlength_datum(values, elemLength, PointerGetDatum(values));
 			values = (char*)att_align_nominal(values, elemAlign);
-#endif
-
 		}
 	}
 	result.l = (jobject)objArray;
diff --git a/pljava-so/src/main/c/type/Oid.c b/pljava-so/src/main/c/type/Oid.c
index aecb67e01..37bb89b2e 100644
--- a/pljava-so/src/main/c/type/Oid.c
+++ b/pljava-so/src/main/c/type/Oid.c
@@ -1,10 +1,14 @@
 /*
- * Copyright (c) 2004, 2005, 2006 TADA AB - Taby Sweden
- * Distributed under the terms shown in the file COPYRIGHT
- * found in the root folder of this project or at
- * http://eng.tada.se/osprojects/COPYRIGHT.html
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
- * @author Thomas Hallgren
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the The BSD 3-Clause License
+ * which accompanies this distribution, and is available at
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Contributors:
+ *   Tada AB
+ *   Chapman Flack
  */
 #include <postgres.h>
 
@@ -256,11 +260,7 @@ Java_org_postgresql_pljava_internal_Oid__1forTypeName(JNIEnv* env, jclass cls, j
 		PG_TRY();
 		{
 			int32 typmod = 0;
-#if PG_VERSION_NUM < 90400
-			parseTypeString(typeNameOrOid, &typeId, &typmod);
-#else
 			parseTypeString(typeNameOrOid, &typeId, &typmod, 0);
-#endif
 		}
 		PG_CATCH();
 		{
diff --git a/pljava-so/src/main/c/type/SQLXMLImpl.c b/pljava-so/src/main/c/type/SQLXMLImpl.c
index 16b483b37..157f4251b 100644
--- a/pljava-so/src/main/c/type/SQLXMLImpl.c
+++ b/pljava-so/src/main/c/type/SQLXMLImpl.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -50,9 +50,7 @@ static bool _SQLXML_canReplaceType(Type self, Type other)
 #if defined(XMLOID)
 		Type_getOid(other) == XMLOID  ||
 #endif
-#if PG_VERSION_NUM >= 90100
 		Type_getOid(other) == PG_NODE_TREEOID  ||  /* a synthetic rendering */
-#endif
 		Type_getOid(other) == TEXTOID;
 }
 
@@ -86,17 +84,12 @@ static Datum _SQLXML_coerceObject(Type self, jobject sqlxml)
 		s_SQLXML_class, s_SQLXML_adopt, sqlxml, Type_getOid(self));
 	Datum d = pljava_VarlenaWrapper_adopt(vw);
 	JNI_deleteLocalRef(vw);
-#if PG_VERSION_NUM >= 90500
 	if ( VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(d)) )
 		return TransferExpandedObject(d, CurrentMemoryContext);
-#endif
-#if PG_VERSION_NUM >= 90200
+
 	MemoryContextSetParent(
 		GetMemoryChunkContext(DatumGetPointer(d)), CurrentMemoryContext);
-#else
-	if ( CurrentMemoryContext != GetMemoryChunkContext(DatumGetPointer(d)) )
-		d = PointerGetDatum(PG_DETOAST_DATUM_COPY(d));
-#endif
+
 	return d;
 }
 
@@ -134,18 +127,15 @@ static Type _SQLXML_obtain(Oid typeId)
 #if defined(XMLOID)
 	static Type xmlInstance;
 #endif
-#if PG_VERSION_NUM >= 90100
 	static Type pgNodeTreeInstance;
-#endif
+
 	switch ( typeId )
 	{
-#if PG_VERSION_NUM >= 90100
 	case PG_NODE_TREEOID:
 		allowedId = PG_NODE_TREEOID;
 		synthetic = true;
 		cache = &pgNodeTreeInstance;
 		break;
-#endif
 	default:
 		if ( TEXTOID == typeId )
 		{
diff --git a/pljava-so/src/main/c/type/String.c b/pljava-so/src/main/c/type/String.c
index e380be326..8b4623942 100644
--- a/pljava-so/src/main/c/type/String.c
+++ b/pljava-so/src/main/c/type/String.c
@@ -226,11 +226,7 @@ text* String_createText(jstring javaString)
 		/* Allocate and initialize the text structure.
 		 */
 		result = (text*)palloc(varSize);
-#if PG_VERSION_NUM < 80300
-		VARATT_SIZEP(result) = varSize;	/* Total size of structure, not just data */
-#else
 		SET_VARSIZE(result, varSize);	/* Total size of structure, not just data */
-#endif
 		memcpy(VARDATA(result), denc, dencLen);
 
 		if(denc != sid.data)
diff --git a/pljava-so/src/main/c/type/Timestamp.c b/pljava-so/src/main/c/type/Timestamp.c
index 2cbdba9ee..7cd76a6c2 100644
--- a/pljava-so/src/main/c/type/Timestamp.c
+++ b/pljava-so/src/main/c/type/Timestamp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2019 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -405,23 +405,7 @@ static Datum _Timestamptz_coerceObject(Type self, jobject ts)
  */
 static int32 Timestamp_getTimeZone(pg_time_t time)
 {
-#if defined(_MSC_VER) && ( \
-	100000<=PG_VERSION_NUM && PG_VERSION_NUM<100002 || \
-	 90600<=PG_VERSION_NUM && PG_VERSION_NUM< 90607 || \
-	 90500<=PG_VERSION_NUM && PG_VERSION_NUM< 90511 || \
-	 90400<=PG_VERSION_NUM && PG_VERSION_NUM< 90416 || \
-	PG_VERSION_NUM < 90321 )
-	/* This is gross, but pg_tzset has a cache, so not as gross as you think.
-	 * There is some renewed interest on pgsql-hackers to find a good answer for
-	 * the MSVC PGDLLIMPORT nonsense, so this may not have to stay gross.
-	 */
-	char const *tzname = PG_GETCONFIGOPTION("timezone");
-	struct pg_tm* tx = pg_localtime(&time, pg_tzset(tzname));
-#elif PG_VERSION_NUM < 80300
-	struct pg_tm* tx = pg_localtime(&time, global_timezone);
-#else
 	struct pg_tm* tx = pg_localtime(&time, session_timezone);
-#endif
 	if ( NULL == tx )
 		ereport(ERROR, (
 			errcode(ERRCODE_DATA_EXCEPTION),
diff --git a/pljava-so/src/main/c/type/Type.c b/pljava-so/src/main/c/type/Type.c
index a0d181e2f..d3dcc50a5 100644
--- a/pljava-so/src/main/c/type/Type.c
+++ b/pljava-so/src/main/c/type/Type.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2022 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -30,42 +30,11 @@
 #include "pljava/HashMap.h"
 #include "pljava/SPI.h"
 
-#if PG_VERSION_NUM < 80300
-typedef enum CoercionPathType
-{
-	COERCION_PATH_NONE, 		/* failed to find any coercion pathway */
-	COERCION_PATH_FUNC, 		/* apply the specified coercion function */
-	COERCION_PATH_RELABELTYPE,  /* binary-compatible cast, no function */
-	COERCION_PATH_ARRAYCOERCE,  /* need an ArrayCoerceExpr node */
-	COERCION_PATH_COERCEVIAIO	/* need a CoerceViaIO node */
-} CoercionPathType;
-
-static CoercionPathType fcp(Oid targetTypeId, Oid sourceTypeId,
-							CoercionContext ccontext, Oid *funcid);
-static CoercionPathType fcp(Oid targetTypeId, Oid sourceTypeId,
-							CoercionContext ccontext, Oid *funcid)
-{
-	if ( find_coercion_pathway(targetTypeId, sourceTypeId, ccontext, funcid) )
-		return *funcid != InvalidOid ?
-			COERCION_PATH_FUNC : COERCION_PATH_RELABELTYPE;
-	else
-		return COERCION_PATH_NONE;
-}
-#define find_coercion_pathway fcp
-#endif
-
-#if PG_VERSION_NUM < 90500
-#define DomainHasConstraints(x) true
-#endif
-
 #if PG_VERSION_NUM < 110000
 static Oid BOOLARRAYOID;
 static Oid CHARARRAYOID;
 static Oid FLOAT8ARRAYOID;
 static Oid INT8ARRAYOID;
-#if PG_VERSION_NUM < 80400
-static Oid INT2ARRAYOID;
-#endif
 #endif
 
 static HashMap s_typeByOid;
@@ -1055,14 +1024,36 @@ void Type_initialize(void)
 	CHARARRAYOID   = get_array_type(CHAROID);
 	FLOAT8ARRAYOID = get_array_type(FLOAT8OID);
 	INT8ARRAYOID   = get_array_type(INT8OID);
-#if PG_VERSION_NUM < 80400
-	INT2ARRAYOID   = get_array_type(INT2OID);
-#endif
 #endif
 
 	initializeTypeBridges();
 }
 
+static Type unimplementedTypeObtainer(Oid typeId);
+static jvalue unimplementedDatumCoercer(Type, Datum);
+static Datum unimplementedObjectCoercer(Type, jobject);
+
+static Type unimplementedTypeObtainer(Oid typeId)
+{
+	ereport(ERROR,
+		(errmsg("no type obtainer registered for type oid %ud", typeId)));
+	pg_unreachable();
+}
+
+static jvalue unimplementedDatumCoercer(Type t, Datum d)
+{
+	ereport(ERROR,
+		(errmsg("no datum coercer registered for type oid %ud", t->typeId)));
+	pg_unreachable();
+}
+
+static Datum unimplementedObjectCoercer(Type t, jobject o)
+{
+	ereport(ERROR,
+		(errmsg("no object coercer registered for type oid %ud", t->typeId)));
+	pg_unreachable();
+}
+
 /*
  * Abstract Type constructor
  */
@@ -1081,8 +1072,8 @@ TypeClass TypeClass_alloc2(
 	self->javaTypeName    = "";
 	self->javaClass       = 0;
 	self->canReplaceType  = _Type_canReplaceType;
-	self->coerceDatum     = (DatumCoercer)_PgObject_pureVirtualCalled;
-	self->coerceObject    = (ObjectCoercer)_PgObject_pureVirtualCalled;
+	self->coerceDatum     = unimplementedDatumCoercer;
+	self->coerceObject    = unimplementedObjectCoercer;
 	self->createArrayType = _Type_createArrayType;
 	self->invoke          = _Type_invoke;
 	self->getSRFCollector = _Type_getSRFCollector;
@@ -1171,9 +1162,7 @@ static void _registerType(
 
 void Type_registerType(const char* javaTypeName, Type type)
 {
-	_registerType(
-		type->typeId, javaTypeName, type,
-		(TypeObtainer)_PgObject_pureVirtualCalled);
+	_registerType(type->typeId, javaTypeName, type, unimplementedTypeObtainer);
 }
 
 void Type_registerType2(
diff --git a/pljava-so/src/main/c/type/UDT.c b/pljava-so/src/main/c/type/UDT.c
index d351038fc..1f33b0afc 100644
--- a/pljava-so/src/main/c/type/UDT.c
+++ b/pljava-so/src/main/c/type/UDT.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -15,6 +15,7 @@
 #include <postgres.h>
 #include <catalog/pg_namespace.h>
 #include <utils/builtins.h>
+#include <utils/bytea.h>
 #include <utils/typcache.h>
 #include <libpq/pqformat.h>
 #include <funcapi.h>
@@ -29,10 +30,6 @@
 #include "pljava/SQLInputFromTuple.h"
 #include "pljava/SQLOutputToTuple.h"
 
-#if PG_VERSION_NUM >= 90000
-#include <utils/bytea.h>
-#endif
-
 /*
  * This code, as currently constituted, makes these assumptions that limit how
  * Java can implement a (scalar) UDT:
@@ -183,11 +180,7 @@ static Datum coerceScalarObject(UDT self, jobject value)
 		{
 			/* Assign the correct length.
 			 */
-#if PG_VERSION_NUM < 80300
-			VARATT_SIZEP(buffer.data) = buffer.len;
-#else
 			SET_VARSIZE(buffer.data, buffer.len);
-#endif
 		}
 		else if(dataLen != buffer.len)
 		{
diff --git a/pljava-so/src/main/c/type/byte_array.c b/pljava-so/src/main/c/type/byte_array.c
index d17630842..91e3103a0 100644
--- a/pljava-so/src/main/c/type/byte_array.c
+++ b/pljava-so/src/main/c/type/byte_array.c
@@ -1,10 +1,14 @@
 /*
- * Copyright (c) 2004, 2005, 2006 TADA AB - Taby Sweden
- * Distributed under the terms shown in the file COPYRIGHT
- * found in the root folder of this project or at
- * http://eng.tada.se/osprojects/COPYRIGHT.html
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
- * @author Thomas Hallgren
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the The BSD 3-Clause License
+ * which accompanies this distribution, and is available at
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Contributors:
+ *   Tada AB
+ *   Chapman Flack
  */
 #include "pljava/Exception.h"
 #include "pljava/type/Type_priv.h"
@@ -40,11 +44,7 @@ static Datum _byte_array_coerceObject(Type self, jobject byteArray)
 		int32  byteaSize = length + VARHDRSZ;
 
 		bytes = (bytea*)palloc(byteaSize);
-#if PG_VERSION_NUM < 80300
-		VARATT_SIZEP(bytes) = byteaSize;
-#else
 		SET_VARSIZE(bytes, byteaSize);
-#endif
 		JNI_getByteArrayRegion((jbyteArray)byteArray, 0, length, (jbyte*)VARDATA(bytes));
 	}
 	else if(JNI_isInstanceOf(byteArray, s_BlobValue_class))
@@ -55,11 +55,7 @@ static Datum _byte_array_coerceObject(Type self, jobject byteArray)
 
 		byteaSize = (int32)(length + VARHDRSZ);
 		bytes = (bytea*)palloc(byteaSize);
-#if PG_VERSION_NUM < 80300
-		VARATT_SIZEP(bytes) = byteaSize;
-#else
 		SET_VARSIZE(bytes, byteaSize);
-#endif
 
 		byteBuffer = JNI_newDirectByteBuffer((void*)VARDATA(bytes), length);
 		if(byteBuffer != 0)
diff --git a/pljava-so/src/main/include/pljava/Backend.h b/pljava-so/src/main/include/pljava/Backend.h
index 16c29cdbd..e0e8ca30b 100644
--- a/pljava-so/src/main/include/pljava/Backend.h
+++ b/pljava-so/src/main/include/pljava/Backend.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -53,13 +53,7 @@ void Backend_warnJEP411(bool isCommit);
 #error The macro PG_GETCONFIGOPTION needs to be renamed.
 #endif
 
-#if PG_VERSION_NUM >= 90100
 #define PG_GETCONFIGOPTION(key) GetConfigOption(key, false, true)
-#elif PG_VERSION_NUM >= 90000
-#define PG_GETCONFIGOPTION(key) GetConfigOption(key, true)
-#else
-#define PG_GETCONFIGOPTION(key) GetConfigOption(key)
-#endif
 
 #ifdef __cplusplus
 }
diff --git a/pljava-so/src/main/include/pljava/Exception.h b/pljava-so/src/main/include/pljava/Exception.h
index a2edad91a..d524dd062 100644
--- a/pljava-so/src/main/include/pljava/Exception.h
+++ b/pljava-so/src/main/include/pljava/Exception.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -17,14 +17,6 @@
 
 #include "pljava/PgObject.h"
 
-#if PG_VERSION_NUM < 90500
-#ifdef __GNUC__
-#define pg_attribute_printf(f,a) __attribute__((format(printf, f, a)))
-#else
-#define pg_attribute_printf(f,a)
-#endif
-#endif
-
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/pljava-so/src/main/include/pljava/PgObject_priv.h b/pljava-so/src/main/include/pljava/PgObject_priv.h
index b179a3b84..4c116b202 100644
--- a/pljava-so/src/main/include/pljava/PgObject_priv.h
+++ b/pljava-so/src/main/include/pljava/PgObject_priv.h
@@ -1,10 +1,14 @@
 /*
- * Copyright (c) 2004, 2005, 2006 TADA AB - Taby Sweden
- * Distributed under the terms shown in the file COPYRIGHT
- * found in the root folder of this project or at
- * http://eng.tada.se/osprojects/COPYRIGHT.html
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
- * @author Thomas Hallgren
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the The BSD 3-Clause License
+ * which accompanies this distribution, and is available at
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Contributors:
+ *   Tada AB
+ *   Chapman Flack
  */
 #ifndef __pljava_PgObject_priv_h
 #define __pljava_PgObject_priv_h
@@ -54,12 +58,6 @@ struct PgObject_
 	PgObjectClass m_class;
 };
 
-/*
- * Internal bogus. Someone forgot to replace a function
- * pointer somewhere.
- */
-extern void _PgObject_pureVirtualCalled(PgObject self);
-
 /*
  * Throw an exception indicating that wanted member could not be
  * found.
diff --git a/pljava-so/src/main/include/pljava/pljava.h b/pljava-so/src/main/include/pljava/pljava.h
index 8da93ff6c..6a2e298c9 100644
--- a/pljava-so/src/main/include/pljava/pljava.h
+++ b/pljava-so/src/main/include/pljava/pljava.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -37,6 +37,7 @@ extern int vsnprintf(char* buf, size_t count, const char* format, va_list arg);
 #include <utils/syscache.h>
 #include <utils/memutils.h>
 #include <tcop/tcopprot.h>
+#include <access/htup_details.h>
 
 /*
  * AssertVariableIsOfType appeared in PG9.3. Can test for the macro directly.
@@ -65,23 +66,6 @@ extern int vsnprintf(char* buf, size_t count, const char* format, va_list arg);
 	ALLOCSET_SMALL_MINSIZE, ALLOCSET_SMALL_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE
 #endif
 
-/*
- * GETSTRUCT require "access/htup_details.h" to be included in PG9.3
- */
-#if PG_VERSION_NUM >= 90300
-#include "access/htup_details.h"
-#endif
-
-/*
- * PG_*_{MIN,MAX} macros (which happen, conveniently, to match Java's datatypes
- * (the signed ones, anyway), appear in PG 9.5. Could test for them directly,
- * but explicit version conditionals may be easier to find and prune when the
- * back-compatibility horizon passes them. Here are only the ones being used.
- */
-#if PG_VERSION_NUM < 90500
-#define PG_INT32_MAX    (0x7FFFFFFF)
-#endif
-
 /*
  * This symbol was spelled without the underscores prior to PG 14.
  */
@@ -118,28 +102,10 @@ extern MemoryContext JavaMemoryContext;
  * stack_base_ptr was static before PG 8.1. By executive decision, PL/Java now
  * has 8.1 as a back compatibility limit; no empty #defines here for earlier.
  */
-#if 90104<=PG_VERSION_NUM || \
-	90008<=PG_VERSION_NUM && PG_VERSION_NUM<90100 || \
-	80412<=PG_VERSION_NUM && PG_VERSION_NUM<90000 || \
-	80319<=PG_VERSION_NUM && PG_VERSION_NUM<80400
 #define NEED_MISCADMIN_FOR_STACK_BASE
 #define _STACK_BASE_TYPE pg_stack_base_t
 #define _STACK_BASE_SET saveStackBasePtr = set_stack_base()
 #define _STACK_BASE_RESTORE restore_stack_base(saveStackBasePtr)
-#else
-extern
-#if PG_VERSION_NUM < 80300
-DLLIMPORT
-#else
-PGDLLIMPORT
-#endif
-char* stack_base_ptr;
-#define _STACK_BASE_TYPE char*
-#define _STACK_BASE_SET \
-	saveStackBasePtr = stack_base_ptr; \
-	stack_base_ptr = (char*)&saveMainThreadId
-#define _STACK_BASE_RESTORE stack_base_ptr = saveStackBasePtr
-#endif
 
 #define STACK_BASE_VARS \
 	void* saveMainThreadId = 0; \
diff --git a/pljava/pom.xml b/pljava/pom.xml
index 83b415529..6c128b8e1 100644
--- a/pljava/pom.xml
+++ b/pljava/pom.xml
@@ -182,11 +182,15 @@ function executeReport(report, locale)
 		 * A special file manager that will rewrite the RELDOTS seen in
 		 * -linkoffline above. The options a file manager recognizes must be the
 		 * first ones in args; handleFirstOptions below returns at the first one
-		 * the file manager doesn't know what to do with.
+		 * the file manager doesn't know what to do with. Java 19 seems to have
+		 * learned to pass the args to the file manager without the fuss here.
 		 */
 		var rmgr = new org.postgresql.pljava.pgxs.RelativizingFileManager(
 			smgr, Charset.forName(report.outputEncoding));
-		rmgr.handleFirstOptions(args);
+
+		var v = java.lang.Runtime.version();
+		if ( 0 > v.compareTo(java.lang.Runtime.Version.parse("19-ea")) )
+			rmgr.handleFirstOptions(args);
 
 		var task = tool.getTask(null, rmgr, diagListener, null, args, null);
 		if (task.call())
diff --git a/pljava/src/main/java/org/postgresql/pljava/internal/InstallHelper.java b/pljava/src/main/java/org/postgresql/pljava/internal/InstallHelper.java
index 67c959122..55e1f76c7 100644
--- a/pljava/src/main/java/org/postgresql/pljava/internal/InstallHelper.java
+++ b/pljava/src/main/java/org/postgresql/pljava/internal/InstallHelper.java
@@ -991,6 +991,7 @@ void migrateFrom( SchemaVariant sv, Connection c, Statement s)
 		UNREL20040120  ("5e4131738cd095b7ff6367d64f809f6cec6a7ba7"),
 		EMPTY          (null);
 
+		static final SchemaVariant REL_1_6_6       = REL_1_6_0;
 		static final SchemaVariant REL_1_6_5       = REL_1_6_0;
 		static final SchemaVariant REL_1_6_4       = REL_1_6_0;
 		static final SchemaVariant REL_1_6_3       = REL_1_6_0;
diff --git a/pljava/src/main/java/org/postgresql/pljava/internal/SPI.java b/pljava/src/main/java/org/postgresql/pljava/internal/SPI.java
index 9151ad100..98ac19932 100644
--- a/pljava/src/main/java/org/postgresql/pljava/internal/SPI.java
+++ b/pljava/src/main/java/org/postgresql/pljava/internal/SPI.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2019 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2004-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -53,6 +53,9 @@ public class SPI
 	public static final int OK_REL_REGISTER     = 15;
 	public static final int OK_REL_UNREGISTER   = 16;
 	public static final int OK_TD_REGISTER      = 17;
+	public static final int OK_MERGE            = 18;
+
+	public static final int OPT_NONATOMIC       = 1 << 0;
 
 	/**
 	 * Execute a command using the internal <code>SPI_exec</code> function.
diff --git a/pljava/src/main/java/org/postgresql/pljava/internal/VarlenaWrapper.java b/pljava/src/main/java/org/postgresql/pljava/internal/VarlenaWrapper.java
index 89594488e..44432000b 100644
--- a/pljava/src/main/java/org/postgresql/pljava/internal/VarlenaWrapper.java
+++ b/pljava/src/main/java/org/postgresql/pljava/internal/VarlenaWrapper.java
@@ -1182,12 +1182,11 @@ public Thread newThread(Runnable r)
 		 * wraps a {@code ByteBuffer} and the {@link Output.State Output.State}
 		 * that protects it.
 		 *<p>
-		 * {@code BufferWrapper} installs <em>itself</em> as the inherited
-		 * {@code m_state} field, so {@code ByteBufferInputStream}'s methods
-		 * synchronize on it rather than the {@code State} object, for no
-		 * interference with the writing thread. The {@code pin} and
-		 * {@code unpin} methods, of course, forward to those of the
-		 * native state object.
+		 * {@code BufferWrapper} installs <em>itself</em> as the
+		 * {@code ByteBufferInputStream}'s lock object, so its methods
+		 * synchronize on this rather than anything that would interfere with
+		 * the writing thread. The {@code pin} and {@code unpin} methods,
+		 * of course, forward to those of the native state object.
 		 */
 		static class BufferWrapper
 		extends ByteBufferInputStream
diff --git a/pljava/src/main/java/org/postgresql/pljava/jdbc/SPIDatabaseMetaData.java b/pljava/src/main/java/org/postgresql/pljava/jdbc/SPIDatabaseMetaData.java
index 1b5de43d6..067bfa0fa 100644
--- a/pljava/src/main/java/org/postgresql/pljava/jdbc/SPIDatabaseMetaData.java
+++ b/pljava/src/main/java/org/postgresql/pljava/jdbc/SPIDatabaseMetaData.java
@@ -1574,7 +1574,11 @@ public java.sql.ResultSet getProcedureColumns(String catalog,
 			// if we are returning a multi-column result.
 			if(returnTypeType.equals("c"))
 			{
-				String columnsql = "SELECT a.attname,a.atttypid FROM pg_catalog.pg_attribute a WHERE a.attrelid = ? ORDER BY a.attnum ";
+				String columnsql =
+					"SELECT a.attname,a.atttypid " +
+					"FROM pg_catalog.pg_attribute a " +
+					"WHERE a.attrelid OPERATOR(pg_catalog.=) ? " +
+					"ORDER BY a.attnum";
 				PreparedStatement stmt = m_connection.prepareStatement(columnsql);
 				stmt.setObject(1, returnTypeRelid);
 				ResultSet columnrs = stmt.executeQuery(columnsql);
@@ -2158,7 +2162,7 @@ public java.sql.ResultSet getTablePrivileges(String catalog,
 
 		String sql = "SELECT n.nspname,c.relname,u.usename,c.relacl "
 				+ " FROM pg_catalog.pg_namespace n, pg_catalog.pg_class c, pg_catalog.pg_user u "
-				+ " WHERE c.relnamespace = n.oid "
+				+ " WHERE c.relnamespace OPERATOR(pg_catalog.=) n.oid "
 				+ " AND u.usesysid OPERATOR(pg_catalog.=) c.relowner "
 				+ " AND c.relkind OPERATOR(pg_catalog.=) 'r' "
                 + " AND " + resolveSchemaPatternCondition(
diff --git a/pljava/src/main/java/org/postgresql/pljava/jdbc/SQLXMLImpl.java b/pljava/src/main/java/org/postgresql/pljava/jdbc/SQLXMLImpl.java
index 1b3bb2a00..bd8c8b64c 100644
--- a/pljava/src/main/java/org/postgresql/pljava/jdbc/SQLXMLImpl.java
+++ b/pljava/src/main/java/org/postgresql/pljava/jdbc/SQLXMLImpl.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2021 Tada AB and other contributors, as listed below.
+ * Copyright (c) 2018-2023 Tada AB and other contributors, as listed below.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the The BSD 3-Clause License
@@ -157,9 +157,13 @@
 /* ... for Adjusting API for Source / Result */
 
 import java.io.StringReader;
+import java.util.List;
+import static javax.xml.XMLConstants.ACCESS_EXTERNAL_DTD;
+import static javax.xml.XMLConstants.ACCESS_EXTERNAL_SCHEMA;
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.validation.Schema;
 import org.postgresql.pljava.Adjusting;
+import static org.postgresql.pljava.Adjusting.XML.setFirstSupported;
 import org.xml.sax.EntityResolver;
 import org.xml.sax.SAXNotRecognizedException;
 import org.xml.sax.SAXNotSupportedException;
@@ -4144,14 +4148,76 @@ Writable finish() throws IOException, SQLException
 	AdjustingJAXPParser<T extends Adjusting.XML.Parsing<T>>
 	implements Adjusting.XML.Parsing<T>
 	{
+		static final Logger s_logger =
+			Logger.getLogger("org.postgresql.pljava.jdbc");
+
+		private static final String JDK17 = "jdk.xml.";
 		private static final String LIMIT =
-			"http://www.oracle.com/xml/jaxp/properties/";
+			"http://www.oracle.com/xml/jaxp/properties/"; // "legacy" since 17
 
-		/*
-		 * Can get these from javax.xml.XMLConstants once assuming Java >= 7.
+		private Exception m_signaling;
+		private Exception m_quiet;
+
+		protected void addSignaling(Exception e)
+		{
+			if ( null == e )
+				return;
+			if ( null == m_signaling )
+				m_signaling = e;
+			else
+				m_signaling.addSuppressed(e);
+		}
+
+		protected void addQuiet(Exception e)
+		{
+			if ( null == e )
+				return;
+			if ( null == m_quiet )
+				m_quiet = e;
+			else
+				m_quiet.addSuppressed(e);
+		}
+
+		protected boolean anySignaling()
+		{
+			return null != m_signaling;
+		}
+
+		/**
+		 * Returns whatever is on the signaling list, while logging (at
+		 * {@code WARNING} level) whatever is on the quiet list.
+		 *<p>
+		 * Both lists are left cleared.
+		 * @return the head exception on the signaling list, or null if none
 		 */
-		private static final String ACCESS =
-			"http://javax.xml.XMLConstants/property/accessExternal";
+		protected Exception exceptions()
+		{
+			Exception e = m_quiet;
+			m_quiet = null;
+			if ( null != e )
+				s_logger.log(WARNING,
+					"some XML processing limits were not successfully adjusted",
+					e);
+			e = m_signaling;
+			m_signaling = null;
+			return e;
+		}
+
+		/**
+		 * Common factor of subclass {@link #lax() lax()} instance methods.
+		 *<p>
+		 * The work is done here, but the instance methods are implemented
+		 * per-subclass to avoid unchecked casting of 'this'.
+		 */
+		protected static void lax(AdjustingJAXPParser o, boolean discard)
+		{
+			if ( null != o.m_quiet )
+			{
+				if ( ! discard )
+					o.addSignaling(o.m_quiet);
+				o.m_quiet = null;
+			}
+		}
 
 		@Override
 		public T defaults()
@@ -4165,6 +4231,7 @@ public T defaults()
 		public T elementAttributeLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "elementAttributeLimit",
 				LIMIT + "elementAttributeLimit");
 		}
 
@@ -4172,6 +4239,7 @@ public T elementAttributeLimit(int limit)
 		public T entityExpansionLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "entityExpansionLimit",
 				LIMIT + "entityExpansionLimit");
 		}
 
@@ -4179,6 +4247,7 @@ public T entityExpansionLimit(int limit)
 		public T entityReplacementLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "entityReplacementLimit",
 				LIMIT + "entityReplacementLimit");
 		}
 
@@ -4186,6 +4255,7 @@ public T entityReplacementLimit(int limit)
 		public T maxElementDepth(int depth)
 		{
 			return setFirstSupportedProperty(depth,
+				JDK17 + "maxElementDepth",
 				LIMIT + "maxElementDepth");
 		}
 
@@ -4193,6 +4263,7 @@ public T maxElementDepth(int depth)
 		public T maxGeneralEntitySizeLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "maxGeneralEntitySizeLimit",
 				LIMIT + "maxGeneralEntitySizeLimit");
 		}
 
@@ -4200,6 +4271,7 @@ public T maxGeneralEntitySizeLimit(int limit)
 		public T maxParameterEntitySizeLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "maxParameterEntitySizeLimit",
 				LIMIT + "maxParameterEntitySizeLimit");
 		}
 
@@ -4207,6 +4279,7 @@ public T maxParameterEntitySizeLimit(int limit)
 		public T maxXMLNameLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "maxXMLNameLimit",
 				LIMIT + "maxXMLNameLimit");
 		}
 
@@ -4214,19 +4287,20 @@ public T maxXMLNameLimit(int limit)
 		public T totalEntitySizeLimit(int limit)
 		{
 			return setFirstSupportedProperty(limit,
+				JDK17 + "totalEntitySizeLimit",
 				LIMIT + "totalEntitySizeLimit");
 		}
 
 		@Override
 		public T accessExternalDTD(String protocols)
 		{
-			return setFirstSupportedProperty(protocols, ACCESS + "DTD");
+			return setFirstSupportedProperty(protocols, ACCESS_EXTERNAL_DTD);
 		}
 
 		@Override
 		public T accessExternalSchema(String protocols)
 		{
-			return setFirstSupportedProperty(protocols, ACCESS + "Schema");
+			return setFirstSupportedProperty(protocols, ACCESS_EXTERNAL_SCHEMA);
 		}
 
 		@Override
@@ -4314,7 +4388,6 @@ static class SAXDOMErrorHandler implements ErrorHandler
 		 */
 		static final Pattern s_wrapelement = Pattern.compile(
 			"^cvc-elt\\.1(?:\\.a)?+:.*pljava-content-wrap");
-		final Logger m_logger = Logger.getLogger("org.postgresql.pljava.jdbc");
 		private int m_wrapCount;
 
 		static SAXDOMErrorHandler instance(boolean wrapped)
@@ -4364,7 +4437,8 @@ public void fatalError(SAXParseException exception) throws SAXException
 		@Override
 		public void warning(SAXParseException exception) throws SAXException
 		{
-			m_logger.log(WARNING, exception.getMessage(), exception);
+			AdjustingJAXPParser.s_logger
+				.log(WARNING, exception.getMessage(), exception);
 		}
 	}
 
@@ -4526,6 +4600,19 @@ public AdjustingSourceResult set(String source)
 			return set(new StreamSource(new StringReader(source)));
 		}
 
+		@Override
+		public AdjustingSourceResult get() throws SQLException
+		{
+			return this; // for this class, get is a noop
+		}
+
+		@Override
+		public AdjustingSourceResult lax(boolean discard)
+		{
+			theAdjustable().lax(discard);
+			return this;
+		}
+
 		@Override
 		public SQLXML getSQLXML() throws SQLException
 		{
@@ -4535,6 +4622,10 @@ public SQLXML getSQLXML() throws SQLException
 			if ( null == m_copier )
 				throw new IllegalStateException(
 					"AdjustingSourceResult getSQLXML called before set");
+
+			// Exception handling/logging for adjustments will happen in
+			// theAdjustable().get(), during finish() here.
+
 			Writable result = null;
 			try
 			{
@@ -4578,12 +4669,6 @@ private Adjusting.XML.Source theAdjustable()
 			return m_copier.getAdjustable();
 		}
 
-		@Override
-		public AdjustingSourceResult get() throws SQLException
-		{
-			return this; // for this class, get is a noop
-		}
-
 		@Override
 		public AdjustingSourceResult allowDTD(boolean v)
 		{
@@ -4748,8 +4833,11 @@ public StreamResult get() throws SQLException
 				throw new IllegalStateException(
 					"AdjustingStreamResult get() called more than once");
 
+			// Exception handling/logging for theVerifierSource happens here
 			XMLReader xr = theVerifierSource().get().getXMLReader();
+
 			OutputStream os;
+
 			try
 			{
 				m_vwo.setVerifier(new Verifier(xr));
@@ -4759,18 +4847,29 @@ public StreamResult get() throws SQLException
 			{
 				throw normalizedException(e);
 			}
+
 			StreamResult sr;
+
 			if ( m_preferWriter )
 				sr = new StreamResult(
 					new OutputStreamWriter(os, m_serverCS.newEncoder()));
 			else
 				sr = new StreamResult(os);
+
 			m_vwo = null;
 			m_verifierSource = null;
 			m_serverCS = null;
+
 			return sr;
 		}
 
+		@Override
+		public AdjustingStreamResult lax(boolean discard)
+		{
+			theVerifierSource().lax(discard);
+			return this;
+		}
+
 		@Override
 		public AdjustingStreamResult allowDTD(boolean v)
 		{
@@ -4860,7 +4959,6 @@ static class AdjustingSAXSource
 		private XMLReader m_xr;
 		private InputSource m_is;
 		private boolean m_wrapped;
-		private SAXException m_except;
 		private boolean m_hasCalledDefaults;
 
 		static class Dummy extends AdjustingSAXSource
@@ -4940,7 +5038,7 @@ private SAXParserFactory theFactory()
 
 		private XMLReader theReader()
 		{
-			if ( null != m_except )
+			if ( anySignaling() )
 				return null;
 
 			if ( null != m_spf )
@@ -4949,16 +5047,12 @@ private XMLReader theReader()
 				{
 					m_xr = m_spf.newSAXParser().getXMLReader();
 				}
-				catch ( SAXException e )
+				catch ( SAXException | ParserConfigurationException e )
 				{
-					m_except = e;
-					return null;
-				}
-				catch ( ParserConfigurationException e )
-				{
-					m_except = new SAXException(e.getMessage(), e);
+					addSignaling(e);
 					return null;
 				}
+
 				m_spf = null;
 				if ( m_wrapped )
 					m_xr = new SAXUnwrapFilter(m_xr);
@@ -4991,9 +5085,11 @@ public SAXSource get() throws SQLException
 				throw new IllegalStateException(
 					"AdjustingSAXSource get() called more than once");
 
-			XMLReader xr;
-			if ( null != m_except  ||  null == (xr = theReader()) )
-				throw normalizedException(m_except);
+			XMLReader xr = theReader();
+
+			Exception e = exceptions();
+			if ( null != e )
+				throw normalizedException(e);
 
 			SAXSource ss = new SAXSource(xr, m_is);
 			m_xr = null;
@@ -5001,6 +5097,13 @@ public SAXSource get() throws SQLException
 			return ss;
 		}
 
+		@Override
+		public AdjustingSAXSource lax(boolean discard)
+		{
+			lax(this, discard);
+			return this;
+		}
+
 		@Override
 		public AdjustingSAXSource defaults()
 		{
@@ -5031,18 +5134,11 @@ public AdjustingSAXSource setFirstSupportedFeature(
 			if ( null == r ) // pending exception, nothing to be done
 				return this;
 
-			for ( String name : names )
-			{
-				try
-				{
-					r.setFeature(name, value);
-					break;
-				}
-				catch ( SAXNotRecognizedException | SAXNotSupportedException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-			}
+			addQuiet(setFirstSupported(r::setFeature, value,
+				List.of(SAXNotRecognizedException.class,
+					SAXNotSupportedException.class),
+				this::addSignaling, names));
+
 			return this;
 		}
 
@@ -5054,22 +5150,11 @@ public AdjustingSAXSource setFirstSupportedProperty(
 			if ( null == r ) // pending exception, nothing to be done
 				return this;
 
-			for ( String name : names )
-			{
-				try
-				{
-					r.setProperty(name, value);
-					break;
-				}
-				catch ( SAXNotRecognizedException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-				catch ( SAXNotSupportedException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-			}
+			addQuiet(setFirstSupported(r::setProperty, value,
+				List.of(SAXNotRecognizedException.class,
+					SAXNotSupportedException.class),
+				this::addSignaling, names));
+
 			return this;
 		}
 
@@ -5141,6 +5226,13 @@ public SAXResult get() throws SQLException
 			return sr;
 		}
 
+		@Override
+		public AdjustingSAXResult lax(boolean discard)
+		{
+			lax(this, discard);
+			return this;
+		}
+
 		@Override
 		public AdjustingSAXResult xIncludeAware(boolean v)
 		{
@@ -5227,6 +5319,8 @@ public StAXSource get() throws SQLException
 			if ( null == m_xif )
 				throw new IllegalStateException(
 					"AdjustingStAXSource get() called more than once");
+
+			StAXSource ss = null;
 			try
 			{
 				XMLStreamReader xsr = m_xif.createXMLStreamReader(
@@ -5234,12 +5328,25 @@ public StAXSource get() throws SQLException
 				if ( m_wrapped )
 					xsr = new StAXUnwrapFilter(xsr);
 				m_xif = null; // too late for any more adjustments
-				return new StAXSource(xsr);
+				ss = new StAXSource(xsr);
 			}
 			catch ( Exception e )
 			{
-				throw normalizedException(e);
+				addSignaling(e);
 			}
+
+			Exception e = exceptions();
+			if ( null != e )
+				throw normalizedException(e);
+
+			return ss;
+		}
+
+		@Override
+		public AdjustingStAXSource lax(boolean discard)
+		{
+			lax(this, discard);
+			return this;
 		}
 
 		@Override
@@ -5286,18 +5393,9 @@ public AdjustingStAXSource setFirstSupportedFeature(
 			boolean value, String... names)
 		{
 			XMLInputFactory xif = theFactory();
-			for ( String name : names )
-			{
-				try
-				{
-					xif.setProperty(name, value);
-					break;
-				}
-				catch ( IllegalArgumentException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-			}
+			addQuiet(setFirstSupported(xif::setProperty, value,
+				List.of(IllegalArgumentException.class),
+				this::addSignaling, names));
 			return this;
 		}
 
@@ -5306,18 +5404,9 @@ public AdjustingStAXSource setFirstSupportedProperty(
 			Object value, String... names)
 		{
 			XMLInputFactory xif = theFactory();
-			for ( String name : names )
-			{
-				try
-				{
-					xif.setProperty(name, value);
-					break;
-				}
-				catch ( IllegalArgumentException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-			}
+			addQuiet(setFirstSupported(xif::setProperty, value,
+				List.of(IllegalArgumentException.class),
+				this::addSignaling, names));
 			return this;
 		}
 	}
@@ -5367,23 +5456,37 @@ public DOMSource get() throws SQLException
 			if ( null == m_dbf )
 				throw new IllegalStateException(
 					"AdjustingDOMSource get() called more than once");
+
+			DOMSource ds = null;
 			try
 			{
 				DocumentBuilder db = m_dbf.newDocumentBuilder();
 				db.setErrorHandler(SAXDOMErrorHandler.instance(m_wrapped));
 				if ( null != m_resolver )
 					db.setEntityResolver(m_resolver);
-				DOMSource ds = new DOMSource(db.parse(m_is));
+				ds = new DOMSource(db.parse(m_is));
 				if ( m_wrapped )
 					domUnwrap(ds);
 				m_dbf = null;
 				m_is = null;
-				return ds;
 			}
 			catch ( Exception e )
 			{
-				throw normalizedException(e);
+				addSignaling(e);
 			}
+
+			Exception e = exceptions();
+			if ( null != e )
+				throw normalizedException(e);
+
+			return ds;
+		}
+
+		@Override
+		public AdjustingDOMSource lax(boolean discard)
+		{
+			lax(this, discard);
+			return this;
 		}
 
 		@Override
@@ -5405,18 +5508,9 @@ public AdjustingDOMSource setFirstSupportedFeature(
 			boolean value, String... names)
 		{
 			DocumentBuilderFactory dbf = theFactory();
-			for ( String name : names )
-			{
-				try
-				{
-					dbf.setFeature(name, value);
-					break;
-				}
-				catch ( ParserConfigurationException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-			}
+			addQuiet(setFirstSupported(dbf::setFeature, value,
+				List.of(ParserConfigurationException.class),
+				this::addSignaling, names));
 			return this;
 		}
 
@@ -5425,18 +5519,9 @@ public AdjustingDOMSource setFirstSupportedProperty(
 			Object value, String... names)
 		{
 			DocumentBuilderFactory dbf = theFactory();
-			for ( String name : names )
-			{
-				try
-				{
-					dbf.setAttribute(name, value);
-					break;
-				}
-				catch ( IllegalArgumentException e )
-				{
-					e.printStackTrace(); // XXX
-				}
-			}
+			addQuiet(setFirstSupported(dbf::setAttribute, value,
+				List.of(IllegalArgumentException.class),
+				this::addSignaling, names));
 			return this;
 		}
 
diff --git a/pljava/src/main/java/org/postgresql/pljava/management/Commands.java b/pljava/src/main/java/org/postgresql/pljava/management/Commands.java
index 0cdafa254..df3884388 100644
--- a/pljava/src/main/java/org/postgresql/pljava/management/Commands.java
+++ b/pljava/src/main/java/org/postgresql/pljava/management/Commands.java
@@ -88,18 +88,18 @@
  * <blockquote><code>SELECT sqlj.install_jar(&lt;jar_url&gt;, &lt;jar_name&gt;, &lt;deploy&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.install_jar(url...)</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.install_jar(url...)</caption>
  * <tr>
- * <td valign="top"><b>jar_url</b></td>
+ * <td><b>jar_url</b></td>
  * <td>The URL that denotes the location of the jar that should be loaded </td>
  * </tr>
  * <tr>
- * <td valign="top"><b>jar_name</b></td>
+ * <td><b>jar_name</b></td>
  * <td>This is the name by which this jar can be referenced once it has been
  * loaded</td>
  * </tr>
  * <tr>
- * <td valign="top"><b>deploy</b></td>
+ * <td><b>deploy</b></td>
  * <td>True if the jar should be deployed according to a {@link
  * org.postgresql.pljava.management.SQLDeploymentDescriptor deployment
  * descriptor}, false otherwise</td>
@@ -109,20 +109,20 @@
  * <blockquote><code>SELECT sqlj.install_jar(&lt;jar_image&gt;, &lt;jar_name&gt;, &lt;deploy&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for
+ * <blockquote><table class="striped"><caption>Parameters for
  * sqlj.install_jar(bytea...)</caption>
  * <tr>
- * <td valign="top"><b>jar_image</b></td>
+ * <td><b>jar_image</b></td>
  * <td>The byte array that constitutes the contents of the jar that should be
  * loaded </td>
  * </tr>
  * <tr>
- * <td valign="top"><b>jar_name</b></td>
+ * <td><b>jar_name</b></td>
  * <td>This is the name by which this jar can be referenced once it has been
  * loaded</td>
  * </tr>
  * <tr>
- * <td valign="top"><b>deploy</b></td>
+ * <td><b>deploy</b></td>
  * <td>True if the jar should be deployed according to a {@link
  * org.postgresql.pljava.management.SQLDeploymentDescriptor deployment
  * descriptor}, false otherwise</td>
@@ -136,17 +136,17 @@
  * <blockquote><code>SELECT sqlj.replace_jar(&lt;jar_url&gt;, &lt;jar_name&gt;, &lt;redeploy&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.replace_jar(url...)</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.replace_jar(url...)</caption>
  * <tr>
- * <td valign="top"><b>jar_url</b></td>
+ * <td><b>jar_url</b></td>
  * <td>The URL that denotes the location of the jar that should be loaded </td>
  * </tr>
  * <tr>
- * <td valign="top"><b>jar_name</b></td>
+ * <td><b>jar_name</b></td>
  * <td>The name of the jar to be replaced</td>
  * </tr>
  * <tr>
- * <td valign="top"><b>redeploy</b></td>
+ * <td><b>redeploy</b></td>
  * <td>True if the old and new jar should be undeployed and deployed according
  * to their respective {@link
  * org.postgresql.pljava.management.SQLDeploymentDescriptor deployment
@@ -157,19 +157,19 @@
  * <blockquote><code>SELECT sqlj.replace_jar(&lt;jar_image&gt;, &lt;jar_name&gt;, &lt;redeploy&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for
+ * <blockquote><table class="striped"><caption>Parameters for
  * sqlj.replace_jar(bytea...)</caption>
  * <tr>
- * <td valign="top"><b>jar_image</b></td>
+ * <td><b>jar_image</b></td>
  * <td>The byte array that constitutes the contents of the jar that should be
  * loaded </td>
  * </tr>
  * <tr>
- * <td valign="top"><b>jar_name</b></td>
+ * <td><b>jar_name</b></td>
  * <td>The name of the jar to be replaced</td>
  * </tr>
  * <tr>
- * <td valign="top"><b>redeploy</b></td>
+ * <td><b>redeploy</b></td>
  * <td>True if the old and new jar should be undeployed and deployed according
  * to their respective {@link
  * org.postgresql.pljava.management.SQLDeploymentDescriptor deployment
@@ -184,13 +184,13 @@
  * <blockquote><code>SELECT sqlj.remove_jar(&lt;jar_name&gt;, &lt;undeploy&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.remove_jar</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.remove_jar</caption>
  * <tr>
- * <td valign="top"><b>jar_name</b></td>
+ * <td><b>jar_name</b></td>
  * <td>The name of the jar to be removed</td>
  * </tr>
  * <tr>
- * <td valign="top"><b>undeploy</b></td>
+ * <td><b>undeploy</b></td>
  * <td>True if the jar should be undeployed according to its {@link
  * org.postgresql.pljava.management.SQLDeploymentDescriptor deployment
  * descriptor}, false otherwise</td>
@@ -204,7 +204,7 @@
  * <blockquote><code>SELECT sqlj.get_classpath(&lt;schema&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.get_classpath</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.get_classpath</caption>
  * <tr>
  * <td><b>schema</b></td>
  * <td>The name of the schema</td>
@@ -219,7 +219,7 @@
  * <blockquote><code>SELECT sqlj.set_classpath(&lt;schema&gt;, &lt;classpath&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.set_classpath</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.set_classpath</caption>
  * <tr>
  * <td><b>schema</b></td>
  * <td>The name of the schema</td>
@@ -236,7 +236,7 @@
  * <blockquote><code>SELECT sqlj.add_type_mapping(&lt;sqlTypeName&gt;, &lt;className&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.add_type_mapping</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.add_type_mapping</caption>
  * <tr>
  * <td><b>sqlTypeName</b></td>
  * <td>The name of the SQL type. The name can be qualified with a
@@ -256,7 +256,7 @@
  * <blockquote><code>SELECT sqlj.drop_type_mapping(&lt;sqlTypeName&gt;);</code>
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.drop_type_mapping</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.drop_type_mapping</caption>
  * <tr>
  * <td><b>sqlTypeName</b></td>
  * <td>The name of the SQL type. The name can be qualified with a
@@ -275,7 +275,7 @@
  * {@code SELECT sqlj.alias_java_language(<alias>, sandboxed => <boolean>);}
  * </blockquote>
  * <h4>Parameters</h4>
- * <blockquote><table><caption>Parameters for sqlj.alias_java_language</caption>
+ * <blockquote><table class="striped"><caption>Parameters for sqlj.alias_java_language</caption>
  * <tr>
  * <td><b>alias</b></td>
  * <td>The name desired for the language alias. Language names are not
diff --git a/src/site/markdown/build/versions.md b/src/site/markdown/build/versions.md
index a759a20b9..75a10ef16 100644
--- a/src/site/markdown/build/versions.md
+++ b/src/site/markdown/build/versions.md
@@ -27,7 +27,7 @@ advances such as [class data sharing][cds].
 Some builds of Java 20 are affected by a bug, [JDK-8309515][]. PL/Java will
 report an error if detects it is affected by that bug, and the solution can be
 to use a Java version earlier than 20, or one recent enough to have the bug
-fixed.
+fixed. The bug is fixed in Java 21.
 
 PL/Java has been successfully used with [Oracle Java][orj] and with
 [OpenJDK][], which is available with
@@ -62,11 +62,11 @@ versions 4.3.0 or later are recommended in order to avoid a
 
 ## PostgreSQL
 
-The PL/Java 1.6 series does not commit to support PostgreSQL earlier than 9.5.
+The PL/Java 1.6 series does not support PostgreSQL earlier than 9.5.
 
 More current PostgreSQL versions, naturally, are the focus of development
 and receive more attention in testing.
 
-PL/Java 1.6.5 has been successfully built and run on at least one platform
-with PostgreSQL versions from 15 to 9.5, the latest maintenance
+PL/Java 1.6.6 has been successfully built and run on at least one platform
+with PostgreSQL versions from 16 to 9.5, the latest maintenance
 release for each.
diff --git a/src/site/markdown/develop/node.md b/src/site/markdown/develop/node.md
index 1011182d2..ae647da14 100644
--- a/src/site/markdown/develop/node.md
+++ b/src/site/markdown/develop/node.md
@@ -51,7 +51,7 @@ installer jar on its classpath, and you have an interactive, scriptable version
 of Java, with the methods of `Node.class` available in it.
 
 The ones that correspond to the Perl example above have the same names, for
-consistency (right down to the Perlish spelling with underscores rather than
+familiarity (right down to the Perlish spelling with underscores rather than
 Javaish camelCase):
 
 ```java
@@ -67,7 +67,8 @@ n1.clean_node()
 `jshell` has to be run with a rather lengthy command line to get to this point;
 more on that later. But once started, it presents a familiar `PostgresNode`-like
 environment. As the example shows, `jshell` is lenient about statement-ending
-semicolons.
+semicolons. (It is still advisable to use them, though; that leniency has fiddly
+exceptions, such as not applying to pasted text.)
 
 ## `Node.class` in detail
 
@@ -102,19 +103,16 @@ The full set of `Node` methods available can be seen
 
 Running `initdb` and starting a server are all well and good, but sooner or
 later a test may need to connect to it. That requires a JDBC driver to be on the
-classpath also: specifically `pgjdbc-ng` (at least, that is the one that's been
-tested and whose URL syntax is built in to `Node`). The older `pgjdbc` punts on
-the correct handling of warning/notice responses from the server, which seems
-rather disqualifying for a testing environment. In `pgjdbc-ng`, notices and
-warnings (any PostgreSQL severity less than `ERROR` and at or above the
-`client_min_messages` setting) are chained together as `SQLWarning` instances,
-as JDBC provides.
-
-A new profile has been added to PL/Java's Maven build, and can be activated with
-`-Ppgjdbc-ng` on the `mvn` command line. It has no effect but to declare an
-extra dependency on the `pgjdbc-ng` dependencies-included jar. It is not used in
-the build, but Maven will have downloaded it to the local repository, and that
-location can be added to `jshell`'s classpath to make the driver available.
+classpath also; either `PGJDBC` or `pgjdbc-ng` will work, with a few minor
+differences.
+
+New profiles have been added to PL/Java's Maven build, and can be activated with
+`-Ppgjdbc` or `-Ppgjdbc-ng` on the `mvn` command line. They have no effect but
+to declare an extra dependency on the corresponding dependencies-included driver
+jar. It is not used in the build, but Maven will have downloaded it to the local
+repository, and that location can be added to `jshell`'s classpath to make the
+driver available. (In the case of `PGJDBC`, adding the jar to the module path
+also works.)
 
 That addition leads to the final long unwieldy command line needed to start
 `jshell`, which can be seen in all its glory toward the end of this page.
@@ -122,12 +120,12 @@ Once that is copied and pasted into a terminal and any local paths changed, the
 rest is easy:
 
 ```java
-import org.postgresql.pljava.packaging.Node
-Node n1 = Node.get_new_node("TestNode1")
-n1.init()
-n1.start()
-import java.sql.Connection
-Connection c1 = n1.connect()
+import org.postgresql.pljava.packaging.Node;
+Node n1 = Node.get_new_node("TestNode1");
+n1.init();
+n1.start();
+import java.sql.Connection;
+Connection c1 = n1.connect();
 ```
 
 Once you have an open connection (or several), the convenience methods `Node`
@@ -138,11 +136,11 @@ parameter.
 
 ```java
 import static org.postgresql.pljava.packaging.Node.qp; // query-print
-qp(c1, "create table foo (bar int, baz text)")
-qp(c1, "insert into foo (values (1, 'Howdy!'))")
-qp(c1, "select 1/0")
-qp(c1, "select pg_sleep(1.5)")
-qp(c1, "select * from foo")
+qp(c1, "CREATE TABLE foo (bar int, baz text)");
+qp(c1, "INSERT INTO foo (VALUES (1, 'Howdy!'))");
+qp(c1, "SELECT 1/0");
+qp(c1, "SELECT pg_sleep(1.5)");
+qp(c1, "SELECT * FROM foo");
 ```
 
 This example shows `qp` used several different ways: with a DDL statement that
@@ -152,18 +150,18 @@ produces a one-row result with one column typed `void` and always null), and one
 that returns a general query result. What it prints:
 
 ```
-jshell> qp(c1, "create table foo (bar int, baz text)")
+jshell> qp(c1, "CREATE TABLE foo (bar int, baz text)");
 
-jshell> qp(c1, "insert into foo (values (1, 'Howdy!'))")
+jshell> qp(c1, "INSERT INTO foo (VALUES (1, 'Howdy!'))");
 <success rows='1'/>
 
-jshell> qp(c1, "select 1/0")
+jshell> qp(c1, "SELECT 1/0");
 <error code='22012' message='division by zero'/>
 
-jshell> qp(c1, "select pg_sleep(1.5)")
+jshell> qp(c1, "SELECT pg_sleep(1.5)");
 <void rows='1' cols='1'/>
 
-jshell> qp(c1, "select * from foo")
+jshell> qp(c1, "SELECT * FROM foo");
       ...
       <column-type-name>text</column-type-name>
     </column-definition>
@@ -192,6 +190,16 @@ the output format consistent. The `void` output is special treatment for
 the common case of a result set with only the `void` column type, to spare the
 effort of generating a whole `WebRowSet` XML that only shows nothing is there.
 
+The results shown above were obtained with `pgjdbc-ng`. If using `PGJDBC`, you
+will notice these minor differences:
+
+* For the first case shown, DDL with no result, `PGJDBC` will present a zero-row
+    success result, the same as for DML that did not affect any rows. This has
+    to be taken into account if writing a state machine to check results, as
+    discussed further below.
+* The `message` attribute produced for an error will have a prefix of `ERROR: `
+    (or the corresponding word in the PostgreSQL server's configured language).
+
 #### `qp` dissected
 
 `qp` is for interactive, exploratory use, generating printed output. For
@@ -206,7 +214,8 @@ update count), or throwables (caught exceptions, or `SQLWarning` instances). The
 JDBC `Statement` is polled for new `SQLWarning`s before checking for each next
 result (`ResultSet` or update count). An error or exception that is thrown and
 caught will be placed on the stream when caught (and will be the last thing on
-the stream).
+the stream, though it may carry chains of cause, suppressed, or next exceptions
+that may follow it if `flattenDiagnostics` is used on the stream).
 
 All 'notices' from PostgreSQL (severity below `ERROR` but at or above
 `client_min_messages`) are turned into `SQLWarning` instances by `pgjdbc-ng`,
@@ -215,6 +224,16 @@ of the details other than the message and SQLState code. `Node` classifies them
 as `info` if the SQLState 'class' (leftmost two positions) is `00`, otherwise as
 `warning`. Exceptions of any other kind are classified as `error`.
 
+`PGJDBC` also turns notices below `ERROR` into `SQLWarning` instances, but
+provides access to the severity tag from the server, so `Node` uses that to
+classify them as `warning` or `info`, instead of the class `00` rule. If the
+severity is `WARNING` (or happens to be null for some reason), `Node` will
+classify the notice as `warning`; any other severity will be classified as
+`info`. (Note, however, that this scheme will not work if the server is
+configured for a language that uses a different word for `WARNING`. To make it
+work in that case, you can call `Node.set_WARNING_localized` in advance, passing
+the word that PostgreSQL uses for `WARNING` in your language.)
+
 As it happens, there is also an overload of `qp` with just one `Stream<Object>`
 parameter. If you have already run a query with `q` and have the result stream,
 and decide you just want to print that, just pass it to `qp`. There are other
@@ -240,15 +259,15 @@ will install it from there, given a path to the repository root and the desired
 version of Saxon-HE. Not to be outdone, `installSaxonAndExamplesAndPath`
 combines the steps in correct order to install the Saxon jar, place it on the
 classpath, install and deploy the examples jar, and set a final classpath that
-installs both.
+includes both.
 
 ```java
-import static java.nio.file.Paths.get
-import java.sql.Connection
-import org.postgresql.pljava.packaging.Node
-import static org.postgresql.pljava.packaging.Node.qp
+import static java.nio.file.Paths.get;
+import java.sql.Connection;
+import org.postgresql.pljava.packaging.Node;
+import static org.postgresql.pljava.packaging.Node.qp;
 
-Node n1 = Node.get_new_node("TestNode1")
+Node n1 = Node.get_new_node("TestNode1");
 
 try (
   AutoCloseable t1 = n1.initialized_cluster();
@@ -273,8 +292,8 @@ try (
   {
     qp(Node.installSaxonAndExamplesAndPath(c,
       get(System.getProperty("user.home"), ".m2", "repository").toString(),
-      "10.2",
-      true))
+      "10.9",
+      true));
   }
 }
 /exit
@@ -290,6 +309,8 @@ would expect of a test.
 Worked-out examples that do the rest of that can be seen in the project
 repository in the configuration files for the CI testing services.
 
+#### `stateMachine` for checking results
+
 One last `Node` method most useful for checking returned results
 programmatically is `stateMachine` (full description in
 [the javadocs][nodeapi]). For example, the `installSaxonAndExamplesAndPath` call
@@ -353,6 +374,36 @@ The `isDiagnostic` method shown above isn't part of the `Node` class; in the
 actual test configurations in the repository, it is trivially defined in
 `jshell` a few lines earlier. Not everything needs to be built in.
 
+The difference in treatment of no-result DDL statements between drivers (where
+`pgjdbc-ng` really has no result, and `PGJDBC` has a zero-row update count as
+it would for a DML statement) can complicate writing a state machine that works
+with both drivers. `Node` predefines a state function
+`NOTHING_OR_PGJDBC_ZERO_COUNT` that consults the `s_urlForm` static field to
+determine which driver is in use, and then moves to the numerically next state,
+after consuming
+
+* nothing, if the driver is `pgjdbc-ng`, or
+* a single zero row count (rejecting any other input), if the driver
+    is `PGJDBC`.
+
+```java
+succeeding &= stateMachine(
+  "descriptive string for this state machine",
+  null,
+
+  q(c, "CREATE TABLE foo (bar int, baz text)")
+  .flatMap(Node::semiFlattenDiagnostics)
+  .peek(Node::peek), // so they also appear in the log
+
+  (o,p,q) -> isDiagnostic(o, Set.of("error")) ? 1 : -2,
+
+  Node.NOTHING_OR_PGJDBC_ZERO_COUNT,
+
+  (o,p,q) -> null == o
+);
+
+```
+
 ## Invoking `jshell` to use `Node.class`
 
 As hinted above, the command needed to get `jshell` started so all the foregoing
@@ -369,7 +420,8 @@ jshell \
 ```
 
 where _$packageJar_ is a PL/Java self-installer jar, _$jdbcJar_ should point
-to a `pgjdbc-ng` "fat jar" (`pgjdbc-ng-all`), and _$pgConfig_ should point to
+to a "fat jar" for the JDBC driver of choice (`postgresql-`_version_`.jar` or
+`pgjdbc-ng-all-`_version_`.jar`), and _$pgConfig_ should point to
 the `pg_config` executable for the PostgreSQL installation that should be used.
 (If there is only one PostgreSQL installation or the right `pg_config` will be
 found on the search path, it doesn't have to be specified.)
@@ -379,13 +431,19 @@ The `-J--add-modules` is needed because even though `jshell` treats
 (because of `--execution local`) wouldn't know that without being told.
 
 The path given to `jshell` itself (`--class-path` without the `-J`) does not
-need to mention the `pgjdbc-ng` jar, because it can be a provider of the
+need to mention _$jdbcJar_, because that can be a provider of the
 `java.sql.Driver` service without having to be visible. If the script will
-want to use `pgjdbc-ng`-specific classes, then the jar does have to be
+want to use driver-specific extension classes, then the jar does have to be
 on `jshell`'s class path too.
 
-The `noUnsafe` setting silences a complaint from the `netty` library
-about Java (correctly!) denying it access to private internals.
+When the driver is `PGJDBC`, it can be placed on the class path or on the module
+path (in which case it becomes the named module `org.postgresql.jdbc`). Again,
+it does not need to be on `jshell`'s module path also---the one without
+`-J`---unless the script will be referring to driver-specific classes.
+
+The `noUnsafe` setting, needed only when the driver is `pgjdbc-ng`, silences
+a complaint from the `netty` library about Java (correctly!) denying it access
+to private internals.
 
 [jshell]: https://docs.oracle.com/en/java/javase/15/jshell/introduction-jshell.html
 [nodeapi]: ../pljava-packaging/apidocs/org/postgresql/pljava/packaging/Node.html#method.summary
diff --git a/src/site/markdown/releasenotes.md.vm b/src/site/markdown/releasenotes.md.vm
index 8f1e17562..a8a1c46c6 100644
--- a/src/site/markdown/releasenotes.md.vm
+++ b/src/site/markdown/releasenotes.md.vm
@@ -10,6 +10,102 @@
 #set($ghbug = 'https://github.com/tada/pljava/issues/')
 #set($ghpull = 'https://github.com/tada/pljava/pull/')
 
+$h2 PL/Java 1.6.6
+
+This is the sixth minor update in the PL/Java 1.6 series. It adds support
+for PostgreSQL 16 and confirms compatibility with Java 21, and fixes some bugs,
+with few other notable changes. Further information on the changes may be found
+below.
+
+$h3 Version compatibility
+
+PL/Java 1.6.6 can be built against recent PostgreSQL versions including 16, and
+older ones back to 9.5, using Java SE 9 or later. The Java version used at
+runtime does not have to be the same version used for building. PL/Java itself
+can run on any Java version 9 or later. PL/Java functions can be
+written for, and use features of, whatever Java version will be loaded at run
+time. See [version compatibility][versions] for more detail.
+
+Some builds of Java 20 are affected by a bug, [JDK-8309515][]. PL/Java will
+report an error if detects it is affected by that bug, and the solution can be
+to use a Java version earlier than 20, or one recent enough to have the bug
+fixed. The bug has been fixed in Java 21.
+
+PL/Java 1.6.6 will definitely no longer build on PostgreSQL versions older
+than 9.5. It has made no attempt to support them since 1.6.0, and lingering
+conditional code for older versions has now been removed.
+
+$h3 Changes
+
+$h4 Changes in XML support
+
+$h5 Java 17's standardized XML feature and property names added
+
+Java 17 added standardized, easy-to-remember names for a number of features and
+properties the underlying XML implementations had formerly supported under
+implementation-specific names. PL/Java's `Adjusting.XML` API already needed to
+know those various other names, to attempt using them to configure the desired
+features and properties. Now it tries the new standard names too.
+
+$h5 Better control when a feature or property can't be set as intended
+
+The original documentation for the feature and property setters in the
+`Adjusting.XML` API said "the adjusting methods are best-effort and do not
+provide an indication of whether the requested adjustment was made". (At the
+same time, failures could produce voluminous output to the log.)
+
+The new [`lax(boolean)`][adjlax] method offers more control. If not used,
+adjustment failures are logged (as before, but more compactly in the case of
+multiple failures in one sequence of adjustments). Or, `lax(true)` can be used
+to silently discard any failures up to that point in a sequence of adjustments,
+or `lax(false)` to have the exceptions chained together and thrown.
+
+The addition of the new Java 17 standardized names can complicate
+version-agnostic configuration of other elements in the Java XML APIs, such as
+`Transformer`, that are not directly covered by PL/Java's
+`Adjusting.XML.Parsing` methods. Client code may find the new `Adjusting.XML`
+method [`setFirstSupported`][adjsfs] convenient for that purpose;
+[an example][egsfs] illustrates.
+
+$h4 Packaging / testing
+
+$h5 Support choice of `PGJDBC` or `pgjdbc-ng` in `Node`
+
+The package jar produced as the last step of the build includes a
+[test harness](develop/node.html) similar to the `PostgresNode` Perl module.
+It formerly worked only with the `pgjdbc-ng` driver. Now it works with either
+`PGJDBC` or `pgjdbc-ng`, and provides features for writing test scripts that
+do not depend on the driver chosen.
+
+$h4 Source code
+
+* Minor changes to support PostgreSQL 16
+* Conditional code supporting PostgreSQL versions older than 9.5 removed
+* Old non-HTML5 elements (rejected by Javadoc 17 and later) removed from
+    doc comments
+* The `pureNonVirtualCalled` method removed to quiet warnings from recent
+    C compilers
+* Schema qualification in embedded SQL added to two operators that had been
+    overlooked in the earlier round of adding such qualification
+$h3 Bugs fixed
+
+* [`NEWLINE` pattern can fail to match](${ghbug}455)
+
+[adjlax]: pljava-api/apidocs/org.postgresql.pljava/org/postgresql/pljava/Adjusting.XML.Parsing.html#method.summary
+[adjsfs]: pljava-api/apidocs/org.postgresql.pljava/org/postgresql/pljava/Adjusting.XML.html#method.detail
+[egsfs]: https://github.com/tada/pljava/blob/V1_6_6/pljava-examples/src/main/java/org/postgresql/pljava/example/annotation/PassXML.java#L528
+
+$h2 Earlier releases
+
+## A nice thing about using Velocity is that each release can be entered at
+## birth using h2 as its main heading, h3 and below within ... and then, when
+## it is moved under 'earlier releases', just define those variables to be
+## one heading level finer. Here goes:
+#set($h2 = '###')
+#set($h3 = '####')
+#set($h4 = '#####')
+#set($h5 = '######')
+
 $h2 PL/Java 1.6.5
 
 This is the fifth minor update in the PL/Java 1.6 series. It adds support
@@ -97,17 +193,6 @@ Tim Van Holder, `aadrian`, `sincatter`, `tayalrun1`.
 [versions]: build/versions.html
 [JDK-8309515]: https://bugs.openjdk.org/browse/JDK-8309515
 
-$h2 Earlier releases
-
-## A nice thing about using Velocity is that each release can be entered at
-## birth using h2 as its main heading, h3 and below within ... and then, when
-## it is moved under 'earlier releases', just define those variables to be
-## one heading level finer. Here goes:
-#set($h2 = '###')
-#set($h3 = '####')
-#set($h4 = '#####')
-#set($h5 = '######')
-
 $h2 PL/Java 1.6.4
 
 This is the fourth minor update in the PL/Java 1.6 series. It is a minor