diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 9de938d3..381e0ff3 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -6,7 +6,11 @@ on:
 jobs:
   natives-linux-windows:
     name: Linux (x86/ARM/PPC) and Windows native library compilation
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:18.04
+      env:
+        GCC: gcc-8
 
     defaults:
       run:
@@ -14,15 +18,20 @@ jobs:
 
     steps:
       - name: Checkout the target branch
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Setup Java
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v3
         with:
+          distribution: temurin
           java-version: 8
+          # Don't need the dependency cache here (or in any of the other native
+          # library compilation steps), because we're not invoking the Java
+          # compiler in this step. We only need the JDK for its headers.
       - name: Install build prerequisites
         run: |
-          sudo apt update
-          sudo make crosstools
+          apt-get update
+          apt-get --assume-yes install make $GCC
+          make crosstools
 
       - name: Build the Linux and Windows native libraries
         run: |
@@ -33,25 +42,25 @@ jobs:
       # exactly to the directories inside `src/main/c/resources/native`. That
       # way, the Java build job can pull down all artifacts and unpack them
       # into that directory to overwrite the versions in-repo. This is sadly
-      # necessary because the actions/download-artifact@v2 action flattens
+      # necessary because the actions/download-artifact@v3 action flattens
       # paths inside artifacts. If it retained full relative paths, we could
       # put Linux and Windows natives inside the same artifact, and we could be
       # flexible with the artifact names. But it doesn't, so we can't, and we
       # can't.
       - name: Upload Linux native libraries
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: linux
           path: src/main/c/resources/native/linux
       - name: Upload Windows native libraries
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: windows
           path: src/main/c/resources/native/windows
 
   natives-macos:
     name: macOS native library compilation
-    runs-on: macos-10.15
+    runs-on: macos-latest
 
     defaults:
       run:
@@ -59,10 +68,11 @@ jobs:
 
     steps:
       - name: Checkout the target branch
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Setup Java
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v3
         with:
+          distribution: temurin
           java-version: 8
 
       - name: Build the macOS native libraries
@@ -71,18 +81,16 @@ jobs:
           make osx
 
       - name: Upload macOS native libraries
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: osx
           path: src/main/c/resources/native/osx/libNRJavaSerial.jnilib
 
   natives-freebsd:
     name: FreeBSD native library compilation
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     container:
-      image: empterdose/freebsd-cross-build:9.3
-      env:
-        JAVA_HOME: /usr/lib/jvm/default-jvm
+      image: empterdose/freebsd-cross-build:11.4
 
     defaults:
       run:
@@ -90,30 +98,35 @@ jobs:
 
     steps:
       - name: Checkout the target branch
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Setup Java
+        uses: actions/setup-java@v3
+        with:
+          distribution: temurin
+          java-version: 8
+      - name: Fake the FreeBSD Java headers
         # This feels extremely dirty, but the only native header we care about
         # is `jni_md.h`, and it is exactly identical between Linux and FreeBSD
         # (at least in OpenJDK 8).
         run: |
-          apk add openjdk8
           ln -s $JAVA_HOME/include/linux $JAVA_HOME/include/freebsd
 
       - name: Build the FreeBSD native libraries
         run: |
           make clean-freebsd
-          settarget i386-freebsd9 make freebsd32
-          settarget x86_64-freebsd9 make freebsd64
+          settarget i386-freebsd11 make freebsd32
+          settarget x86_64-freebsd11 make freebsd64
+          settarget arm64-freebsd11 make freebsdarm64v8
 
       - name: Upload FreeBSD native libraries
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: freebsd
           path: src/main/c/resources/native/freebsd
 
   java:
     name: Java compilation
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
 
     needs:
       - natives-linux-windows
@@ -126,18 +139,20 @@ jobs:
       # don't regress formatting when compared with the master branch, we need
       # to have a local copy of the master branch for comparison.
       - name: Checkout the master branch
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           ref: master
       - name: Checkout the target branch
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Setup Java
-        uses: actions/setup-java@v1
+        uses: actions/setup-java@v3
         with:
+          distribution: temurin
           java-version: 8
+          cache: gradle
 
       - name: Download native libraries
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v3
         with:
           path: src/main/c/resources/native
 
@@ -146,9 +161,9 @@ jobs:
 
       - name: Determine commit hash for artifact filename
         id: vars
-        run: echo "::set-output name=short-rev::$(git rev-parse --short HEAD)"
+        run: echo "short-rev=$(git rev-parse --short HEAD)" >>$GITHUB_OUTPUT
       - name: Upload build artifacts
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: nrjavaserial-${{steps.vars.outputs.short-rev}}
           path: build/libs/*.jar
diff --git a/README.md b/README.md
index b7425ad9..34a00e6f 100644
--- a/README.md
+++ b/README.md
@@ -70,6 +70,13 @@ ease of use and embeddability in other libraries.
 
 The resulting JAR will be found in the `build/libs/` directory.
 
+Optionally, you can publish (“install”) your new build
+into your local Maven repository (`~/.m2/repository`).
+That way, you easily can consume your own build of the library
+from other locally-built Maven/Gradle projects.
+
+    $ ./gradlew publishToMavenLocal
+
 # Building the native libraries
 
 The native libraries are written in C,
diff --git a/build.gradle b/build.gradle
index a073dac8..7994d5ce 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,80 +1,97 @@
 plugins {
-	id "biz.aQute.bnd.builder" version "5.0.1"
-	id "com.diffplug.spotless" version "5.9.0"
+	id 'base'
+	// The application of the Bnd plugin triggers a Gradle warning:
+	//
+	//     The AbstractTask.getConvention() method has been deprecated. This is
+	//     scheduled to be removed in Gradle 9.0. Consult the upgrading guide
+	//     for further information: https://docs.gradle.org/8.3/userguide/
+	//     upgrading_version_8.html#deprecated_access_to_conventions
+	//
+	// This warning is caused by Bnd itself, and there is nothing we can do
+	// about it in our own configuration. This will be resolved [in Bnd v7.0].
+	//
+	// [in Bnd v7.0]: https://github.com/bndtools/bnd/issues/5714#issuecomment-1635684935
+	id 'biz.aQute.bnd.builder' version '6.4.0'
+	// This is the [last version] of Spotless which runs on Java 8. Even though
+	// our toolchain configuration allows us to run Gradle on a higher Java
+	// version than we use to build, Java 8 is a pretty fixed target, so as
+	// long as we're not able to take advantage of any newer language features,
+	// we're probably not losing much by sticking with an older linter.
+	//
+	// [last version]: https://github.com/diffplug/spotless/issues/1337
+	// [toolchain]: https://docs.gradle.org/current/userguide/toolchains.html
+	id 'com.diffplug.spotless' version '6.13.0'
+	id 'eclipse'
+	id 'java'
+	id 'maven-publish'
+	id 'signing'
 }
 
-apply plugin: 'java'
-apply plugin: 'eclipse'
-apply plugin: 'maven'
-apply plugin: 'signing'
-
 [compileJava, compileTestJava]*.options*.encoding = 'UTF-8'
 
-File buildDir = file(".");
+File buildDir = file('.');
 Properties props = new Properties()
-props.load(new FileInputStream(buildDir.getAbsolutePath() + "/src/main/resources/com/neuronrobotics/nrjavaserial/build.properties"))
+props.load(new FileInputStream("${buildDir.getAbsolutePath()}/src/main/resources/com/neuronrobotics/nrjavaserial/build.properties"))
 
-group = "com.neuronrobotics"
-archivesBaseName = "nrjavaserial"
-version = props."app.version"
+group = 'com.neuronrobotics'
+base.archivesName = props.'app.name'
+version = props.'app.version'
 
 sourceSets {
 	test {
 		java {
-			srcDirs = ["test/src"]
+			srcDirs = ['test/src']
 		}
 	}
 	main {
 		resources {
-			srcDirs = ["src/main/resources", "src/main/c/resources"]
-			includes = ["**/*.so","**/*.dll", "**/*.jnilib","**/*.properties"]
+			srcDirs = ['src/main/resources', 'src/main/c/resources']
+			includes = ['**/*.so','**/*.dll', '**/*.jnilib', '**/*.properties']
 		}
 	}
 }
 
-jar.archiveName = "nrjavaserial-${props.'app.version'}.jar"
-
 repositories {
 	mavenCentral()
-	jcenter()
 }
 
 dependencies {
-	compile fileTree(dir: 'libs', includes: ['*.jar'])
-	testCompile 'junit:junit:4.12'
-	compile 'commons-net:commons-net:3.9.0'
+	testImplementation 'junit:junit:4.12'
+	implementation 'commons-net:commons-net:3.9.0'
 	compileOnly 'net.java.dev.jna:jna:4.4.0'
 	compileOnly 'net.java.dev.jna:jna-platform:4.4.0'
 }
 
-jar {
-	jar.duplicatesStrategy = DuplicatesStrategy.EXCLUDE
-
-	bnd("Created-By": "Commonwealth Robotics Cooperative",
-		"Specification-Title": props."app.name",
-		"Specification-Version": props."app.version",
-		"Specification-Vendor": "Commonwealth Robotics Cooperative",
-		"Implementation-Title": props."app.name",
-		"Implementation-Version" : props."app.version",
-		"Implementation-Vendor": "Commonwealth Robotics Cooperative",
-		"Import-Package": "com.sun.jna.platform.win32;resolution:=optional,org.apache.commons.net.telnet;resolution:=optional,!gnu.io*,*",
-		"Export-Package": "gnu.io*"
-	)
-
-}
+java {
+	toolchain {
+		languageVersion = JavaLanguageVersion.of(8)
+	}
 
-task javadocJar(type: Jar) {
-	classifier = 'javadoc'
-	from javadoc
+	withJavadocJar()
+	withSourcesJar()
 }
 
-task sourcesJar(type: Jar) {
-	classifier = 'sources'
-	from (sourceSets.main.allSource) {
-		exclude 'native/'
+jar {
+	bundle {
+		bnd(
+			'Specification-Title': props.'app.name',
+			'Specification-Version': props.'app.version',
+			'Specification-Vendor': 'Commonwealth Robotics Cooperative',
+			'Implementation-Title': props.'app.name',
+			'Implementation-Version' : props.'app.version',
+			'Implementation-Vendor': 'Commonwealth Robotics Cooperative',
+			'Import-Package': 'com.sun.jna.platform.win32;resolution:=optional,org.apache.commons.net.telnet;resolution:=optional,!gnu.io*,*',
+			'Export-Package': 'gnu.io*',
+		)
 	}
 }
 
+// withSourcesJar() creates the sourcesJar task which, by default, packages
+// sourceSets.main.allSource. Including native libraries in this source set is
+// the easiest way to include them the final library archive, but we don't want
+// an extra half meg of binaries to be included in the source archive.
+sourcesJar.exclude('native/')
+
 spotless {
 	enforceCheck false
 	ratchetFrom 'origin/master'
@@ -93,84 +110,146 @@ spotless {
 		eclipse()
 	}
 }
-/*
-signing {
-	required {
-		gradle.taskGraph.hasTask("uploadArchives")
-	}
-	sign configurations.archives
-}
 
-artifacts {
-	archives javadocJar
-	archives sourcesJar
-	archives jar
-}
-
-//import org.gradle.plugins.signing.Sign
-//
-//gradle.taskGraph.whenReady { taskGraph ->
-//	if (taskGraph.allTasks.any { it instanceof Sign }) {
-//		// Use Java 6's console to read from the console (no good for
-//		// a CI environment)
-//		Console console = System.console()
-//		console.printf "\n\nWe have to sign some things in this build." +
-//					   "\n\nPlease enter your signing details.\n\n"
+// You can provide OSSRH publication credentials in three ways. Either:
 //
-//		def id = console.readLine("PGP Key Id: ")
-//		def file = console.readLine("PGP Secret Key Ring File (absolute path): ")
-//		def password = console.readPassword("PGP Private Key Password: ")
+// 1. Pass the username and password properties – ossrhUsername and
+//    ossrhPassword – on the command line:
 //
-//		allprojects { ext."signing.keyId" = id }
-//		allprojects { ext."signing.secretKeyRingFile" = file }
-//		allprojects { ext."signing.password" = password }
+//     ./gradlew ... -PossrhUsername=username -PossrhPassword=password
 //
-//		console.printf "\nThanks.\n\n"
-//	}
-//}
+// 2. Configure those properties in ~/.gradle/gradle.properties.
+// 3. Set the OSSRHUSERNAME and OSSRHPASSWORD environment variables to the
+//    username and password, respectively.
+publishing {
+	def ossrhUsername = findProperty('ossrhUsername')
+	def ossrhPassword = findProperty('ossrhPassword')
+
+	if (System.env.OSSRHUSERNAME && System.env.OSSRHPASSWORD) {
+		ossrhUsername = System.env.OSSRHUSERNAME
+		ossrhPassword = System.env.OSSRHPASSWORD
+	}
 
-uploadArchives {
 	repositories {
-		mavenDeployer {
-			beforeDeployment { MavenDeployment deployment -> signing.signPom(deployment) }
-
-		repository(url: "https://oss.sonatype.org/service/local/staging/deploy/maven2/") {
-			authentication(userName: ossrhUsername, password: ossrhPassword)
+		// A Nexus Repository instance running on localhost. Useful for
+		// debugging the publishing process. Named “localhost”, not “local”, to
+		// avoid confusion with the publishToMavenLocal task, which publishes
+		// to the local Maven cache at ~/.m2/repository.
+		maven {
+			name = 'localhost'
+			url = 'http://localhost:8081/repository/maven-releases/'
+			allowInsecureProtocol = true
+			credentials {
+				username = ossrhUsername
+				password = ossrhPassword
+			}
 		}
 
-		snapshotRepository(url: "https://oss.sonatype.org/content/repositories/snapshots/") {
-			authentication(userName: ossrhUsername, password: ossrhPassword)
+		maven {
+			name = 'ossrh'
+			url = 'https://oss.sonatype.org/service/local/staging/deploy/maven2/'
+			credentials {
+				username = ossrhUsername
+				password = ossrhPassword
+			}
 		}
 
+		maven {
+			name = 'ossrhSnapshots'
+			url = 'https://oss.sonatype.org/content/repositories/snapshots/'
+			credentials {
+				username = ossrhUsername
+				password = ossrhPassword
+			}
+		}
+	}
 
-			pom.project {
-				name 'NRJavaSerial'
-				packaging 'jar'
-				description 'A fork of the RXTX library with a focus on ease of use and embeddability in other libraries.'
-				url 'http://neuronrobotics.com'
+	publications {
+		nrJavaSerial(MavenPublication) {
+			pom {
+				// By default, the artifact ID is derived from the name of the
+				// directory housing this file. If we don't specifically
+				// override that, we'll end up with an unexpected artifact ID
+				// if the project directory is called something other than
+				// “nrjavaserial”.
+				artifactId = props.'app.name'
+				name = 'NRJavaSerial'
+				description = 'A fork of the RXTX library with a focus on ease of use and embeddability in other libraries.'
+				url = 'https://nrjs.org'
+
+				from components.java
 
 				scm {
-					connection			'scm:git:https://github.com/NeuronRobotics/nrjavaserial.git'
-					developerConnection	'scm:git:git@github.com:NeuronRobotics/nrjavaserial.git'
-					url					'https://github.com/NeuronRobotics/nrjavaserial'
+					connection = 'scm:git:https://github.com/NeuronRobotics/nrjavaserial.git'
+					developerConnection = 'scm:git:git@github.com:NeuronRobotics/nrjavaserial.git'
+					url = 'https://github.com/NeuronRobotics/nrjavaserial'
 				}
 
 				licenses {
 					license {
-						name	'The Apache License, Version 2.0'
-						url		'http://www.apache.org/licenses/LICENSE-2.0.txt'
+						name = 'RXTX License v 2.1 - LGPL v 2.1 + Linking Over Controlled Interface'
+						url = 'https://raw.githubusercontent.com/NeuronRobotics/nrjavaserial/master/LICENSE'
 					}
 				}
 
 				developers {
 					developer {
-						id		'madhephaestus'
-						name	'Kevin Harrington'
-						email	'kharrington@neuronrobotics.com'
+						id = 'madhephaestus'
+						name = 'Kevin Harrington'
+						email = 'kharrington@neuronrobotics.com'
+					}
+					developer {
+						id = 'MrDOS'
+						name = 'Samuel Coleman'
+						email = 'samuel@seenet.ca'
 					}
 				}
 			}
 		}
 	}
 }
-*/
+
+// You can provide a signatory in three ways. Either:
+//
+// 1. Pass the signatory properties – signing.keyId, signing.secretKeyRingFile,
+//    and signing.password – on the command line:
+//
+//     ./gradlew ... \
+//         -Psigning.keyId=7FD6B0A1 \
+//         -Psigning.secretKeyRingFile=/path/to/.gnupg/secring.gpg \
+//         -Psigning.password=secret
+//
+// 2. Configure those properties in ~/.gradle/gradle.properties.
+// 3. Set the SIGNINGKEY and SIGNINGPASSWORD environment variables to an
+//    ASCII-armored PGP key and password, respectively.
+//
+// For more details on the behaviour of the properties and their expected
+// values, see the signing plugin documentation:
+//
+//     https://docs.gradle.org/current/userguide/signing_plugin.html#sec:signatory_credentials
+//
+// If a signatory has not been configured, or if the signing.skip property is
+// set, artifacts will not be signed prior to publication.
+//
+// This signing block must appear after the publishing block in order to refer
+// to the specific publication to be signed.
+signing {
+	if (project.hasProperty('signing.skip')) {
+		// We've been explicitly told not to sign artifacts, even if we have a
+		// configured signatory.
+		return
+	} else if (System.env.SIGNINGKEY && System.env.SIGNINGPASSWORD) {
+		useInMemoryPgpKeys(System.env.SIGNINGKEY, System.env.SIGNINGPASSWORD)
+	} else if (findProperty('signing.keyId') &&
+		findProperty('signing.secretKeyRingFile') &&
+		findProperty('signing.password')) {
+		// No special configuration necessary for properties: the signing plugin
+		// self-configures from the signing.keyId, signing.secretKeyRingFile, and
+		// signing.password properties when populated.
+	} else {
+		// No signatory is configured; skip signing.
+		return
+	}
+
+	sign publishing.publications.nrJavaSerial
+}
diff --git a/gradle.properties b/gradle.properties
deleted file mode 120000
index 4e89a6ba..00000000
--- a/gradle.properties
+++ /dev/null
@@ -1 +0,0 @@
-/home/hephaestus/gradle.properties
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index f3d88b1c..7f93135c 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index b7c8c5db..ac72c34e 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index 2fe81a7d..0adc8e1a 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,78 +17,111 @@
 #
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
+
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -97,87 +130,120 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
 fi
 
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
     # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
         fi
-        i=`expr $i + 1`
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
     done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
-    esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index 9109989e..6689b85b 100755
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,7 +41,7 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if %ERRORLEVEL% equ 0 goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -54,7 +55,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -64,38 +65,26 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/settings.gradle b/settings.gradle
new file mode 100644
index 00000000..208c9255
--- /dev/null
+++ b/settings.gradle
@@ -0,0 +1,3 @@
+plugins {
+	id 'org.gradle.toolchains.foojay-resolver-convention' version '0.7.0'
+}
diff --git a/src/main/c/Makefile b/src/main/c/Makefile
index d9569ddf..837a9d79 100644
--- a/src/main/c/Makefile
+++ b/src/main/c/Makefile
@@ -58,6 +58,14 @@ include JAVA_HOME.mk
 
 include platform.mk
 
+# Most of the time, GCC is called `gcc` and is installed from a `gcc` package.
+# However, sometimes a distribution packages multiple versions of GCC. In this
+# case, both the binary and package names of non-default versions are suffixed
+# (e.g., `gcc-8`). We can't use the standard CC variable to adapt to this,
+# because each target already overrides that variable with the name of the
+# appropriate cross compiler.
+GCC ?= gcc
+
 # In all cases, we want to include the system JNI headers, our own headers,
 # crank the optimization level, and compile position-independent code so that
 # it will work as a library (dlopen(3) et al. can load it into any memory).
@@ -87,13 +95,13 @@ all:
 	$(error $(NO_TARGET_PLATFORM_SPECIFIED))
 
 crosstools:
-	apt install --install-recommends \
-	            gcc-i686-linux-gnu \
-	            gcc-arm-linux-gnueabi \
-	            gcc-arm-linux-gnueabihf \
-	            gcc-aarch64-linux-gnu \
+	apt-get --assume-yes install \
+	            $(GCC)-i686-linux-gnu \
+	            $(GCC)-arm-linux-gnueabi \
+	            $(GCC)-arm-linux-gnueabihf \
+	            $(GCC)-aarch64-linux-gnu \
 	            gcc-mingw-w64 \
-	            gcc-powerpc-linux-gnu
+	            $(GCC)-powerpc-linux-gnu
 
 # Does not include Android, because Android toolchains are large, not commonly
 # available, and the resulting library is not typically desired.
@@ -108,7 +116,7 @@ LINUX_CFLAGS += -U_FORTIFY_SOURCE
 endif
 
 # Requires gcc-i686-linux-gnu.
-linux32: export CC := i686-linux-gnu-gcc
+linux32: export CC := i686-linux-gnu-$(GCC)
 linux32: export CFLAGS += $(LINUX_CFLAGS) -m32
 linux32: export LDFLAGS += -m32
 linux32: export platform := linux/x86_32
@@ -116,6 +124,7 @@ linux32:
 	$(MAKE) -f natives.mk
 
 # Requires gcc.
+linux64: export CC := $(GCC)
 linux64: export CFLAGS += $(LINUX_CFLAGS) -m64
 linux64: export platform := linux/x86_64
 linux64:
@@ -127,7 +136,7 @@ arm: arm32v5 \
      arm32v8 arm32v8HF arm64v8
 
 # Requires gcc-arm-linux-gnueabi.
-arm32v5: export CC := arm-linux-gnueabi-gcc
+arm32v5: export CC := arm-linux-gnueabi-$(GCC)
 arm32v5: export CFLAGS += $(LINUX_CFLAGS) -march=armv5t
 arm32v5: export LDFLAGS += -march=armv5t
 arm32v5: export platform := linux/ARM_32
@@ -136,7 +145,7 @@ arm32v5:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-arm-linux-gnueabi.
-arm32v6: export CC := arm-linux-gnueabi-gcc
+arm32v6: export CC := arm-linux-gnueabi-$(GCC)
 arm32v6: export CFLAGS += $(LINUX_CFLAGS) -march=armv6
 arm32v6: export LDFLAGS += -march=armv6
 arm32v6: export platform := linux/ARM_32
@@ -145,16 +154,16 @@ arm32v6:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-arm-linux-gnueabihf.
-arm32v6HF: export CC := arm-linux-gnueabihf-gcc
-arm32v6HF: export CFLAGS += $(LINUX_CFLAGS) -march=armv6 -mfpu=vfp -marm
-arm32v6HF: export LDFLAGS += -march=armv6 -mfpu=vfp -marm
+arm32v6HF: export CC := arm-linux-gnueabihf-$(GCC)
+arm32v6HF: export CFLAGS += $(LINUX_CFLAGS) -march=armv6+fp -marm
+arm32v6HF: export LDFLAGS += -march=armv6+fp -marm
 arm32v6HF: export platform := linux/ARM_32
 arm32v6HF: export variant := v6_HF
 arm32v6HF:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-arm-linux-gnueabi.
-arm32v7: export CC := arm-linux-gnueabi-gcc
+arm32v7: export CC := arm-linux-gnueabi-$(GCC)
 arm32v7: export CFLAGS += $(LINUX_CFLAGS) -march=armv7-a
 arm32v7: export LDFLAGS += -march=armv7-a
 arm32v7: export platform := linux/ARM_32
@@ -163,16 +172,16 @@ arm32v7:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-arm-linux-gnueabihf.
-arm32v7HF: export CC := arm-linux-gnueabihf-gcc
-arm32v7HF: export CFLAGS += $(LINUX_CFLAGS) -march=armv7-a
-arm32v7HF: export LDFLAGS += -march=armv7-a
+arm32v7HF: export CC := arm-linux-gnueabihf-$(GCC)
+arm32v7HF: export CFLAGS += $(LINUX_CFLAGS) -march=armv7-a+fp
+arm32v7HF: export LDFLAGS += -march=armv7-a+fp
 arm32v7HF: export platform := linux/ARM_32
 arm32v7HF: export variant := v7_HF
 arm32v7HF:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-arm-linux-gnueabi.
-arm32v8: export CC := arm-linux-gnueabi-gcc
+arm32v8: export CC := arm-linux-gnueabi-$(GCC)
 arm32v8: export CFLAGS += $(LINUX_CFLAGS) -march=armv8-a
 arm32v8: export LDFLAGS += -march=armv8-a
 arm32v8: export platform := linux/ARM_32
@@ -181,18 +190,18 @@ arm32v8:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-arm-linux-gnueabihf.
-arm32v8HF: export CC := arm-linux-gnueabihf-gcc
-arm32v8HF: export CFLAGS += $(LINUX_CFLAGS) -march=armv8-a
-arm32v8HF: export LDFLAGS += -march=armv8-a
+arm32v8HF: export CC := arm-linux-gnueabihf-$(GCC)
+arm32v8HF: export CFLAGS += $(LINUX_CFLAGS) -march=armv8-a -mfpu=neon-fp-armv8
+arm32v8HF: export LDFLAGS += -march=armv8-a -mfpu=neon-fp-armv8
 arm32v8HF: export platform := linux/ARM_32
 arm32v8HF: export variant := v8_HF
 arm32v8HF:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-aarch64-linux-gnu.
-arm64v8: export CC := aarch64-linux-gnu-gcc
-arm64v8: export CFLAGS += $(LINUX_CFLAGS) -march=armv8-a
-arm64v8: export LDFLAGS += -march=armv8-a
+arm64v8: export CC := aarch64-linux-gnu-$(GCC)
+arm64v8: export CFLAGS += $(LINUX_CFLAGS) -march=armv8-a+fp
+arm64v8: export LDFLAGS += -march=armv8-a+fp
 arm64v8: export platform := linux/ARM_64
 arm64v8: export variant := v8
 arm64v8:
@@ -208,15 +217,19 @@ android:
 	$(MAKE) -f natives.mk
 
 # Requires gcc-powerpc-linux-gnu.
-ppc: export CC := powerpc-linux-gnu-gcc
+ppc: export CC := powerpc-linux-gnu-$(GCC)
 ppc: export CFLAGS += $(LINUX_CFLAGS)
 ppc: export platform := linux/PPC
 ppc:
 	$(MAKE) -f natives.mk
 
 # Requires a macOS host.
-osx: export CFLAGS += -I$(JAVA_HOME)/include/darwin -arch x86_64
-osx: export LDFLAGS := -arch x86_64 -dynamiclib -framework JavaVM -framework IOKit -framework CoreFoundation
+osx: export CFLAGS += -I$(JAVA_HOME)/include/darwin \
+                      -target x86_64-apple-macos10.7
+osx: export LDFLAGS := -target x86_64-apple-macos10.7 \
+                       -dynamiclib \
+                       -framework IOKit \
+                       -framework CoreFoundation
 osx: export objects := fuserImp.o SerialImp.o
 osx: export platform := osx
 osx: export lib_type := jnilib