diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 415913708..1050497d7 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -290,18 +290,25 @@ jobs:
           # (which is not yet generated) uses a real certificate that will be supplied by Signpath and will be suitable
           # for signing released versions of the application.
           #
-          # Select "release-signing" policy for things we're going to release and "test-signing" otherwise.
+          # Ideally we would select "release-signing" policy for things we're going to release and "test-signing"
+          # otherwise, according to the following logic:
           #
-          # Currently our main branch for releasing is called "develop", but we'll probably change it to "main" in the
-          # not too distant future.
+          #   - Currently our main branch for releasing is called "develop", but we'll probably change it to "main" in
+          #     the not too distant future.
           #
-          # We don't do release branches per se, but, before we do a lot of commits for a major release, we'll usually
-          # cut a "stable/" branch for the prior one.
+          #   - We don't do release branches per se, but, before we do a lot of commits for a major release, we'll
+          #     usually cut a "stable/" branch for the prior one.
           #
-          SIGNPATH_SIGNING_POLICY_SLUG: |
-            ${{ (github.ref == 'refs/heads/develop' ||
-                 github.ref == 'refs/heads/main' ||
-                 startsWith(github.ref, 'refs/heads/stable/')) && 'release-signing' || 'test-signing' }}
+          # NOTE HOWEVER that, for automated builds, we comment out this logic and always use the "test-signing" policy.
+          # This is because, on the free tier of SignPath, all release signings need to be manually approved.  (And by
+          # the time a manual approval has happened, the GitHub action will have timed out waiting for it.)  So,
+          # instead, we do our release signings via manual upload to the SignPath service.
+          #
+#          SIGNPATH_SIGNING_POLICY_SLUG: |
+#            ${{ (github.ref == 'refs/heads/develop' ||
+#                 github.ref == 'refs/heads/main' ||
+#                 startsWith(github.ref, 'refs/heads/stable/')) && 'release-signing' || 'test-signing' }}
+          SIGNPATH_SIGNING_POLICY_SLUG: 'test-signing'
         with:
           api-token: '${{ secrets.SIGNPATH_API_TOKEN }}'
           organization-id: '${{ vars.SIGNPATH_ORGANIZATION_ID }}'
diff --git a/CHANGES.markdown b/CHANGES.markdown
index 2eff6e469..9ef8d6b68 100644
--- a/CHANGES.markdown
+++ b/CHANGES.markdown
@@ -20,10 +20,11 @@ Bug fixes and minor enhancements.
 * None
 
 ### Bug Fixes
-*  Some input fields not wide enough on various editors [849](https://github.com/Brewtarget/brewtarget/issues/849)
+* Some input fields not wide enough on various editors [849](https://github.com/Brewtarget/brewtarget/issues/849)
+* Upgrade to Qt 6 [841](https://github.com/Brewtarget/brewtarget/issues/841)
 
 ### Release Timestamp
-Mon, 7 Oct 2024 04:00:06 +0100
+Fri, 11 Oct 2024 04:00:07 +0100
 
 ## v4.0.6
 Bug fixes for the 4.0.5 release (ie bugs in 4.0.5 are fixed in this 4.0.6 release).
diff --git a/schemas/beerxml/v1/BeerXml.xsd b/schemas/beerxml/v1/BeerXml.xsd
index cd323de73..ff520baec 100644
--- a/schemas/beerxml/v1/BeerXml.xsd
+++ b/schemas/beerxml/v1/BeerXml.xsd
@@ -22,7 +22,7 @@
   General Notes:
 
   It is not possible to validate a BeerXML 1.0 document solely with an XSD file, for reasons that are explained in the
-  Brewtarget C++ source code.  Nevertheless, this file goes some considerable way to doing such validation.
+  Brewtarget/Brewken C++ source code.  Nevertheless, this file goes some considerable way to doing such validation.
 
   Although they are generally helpful examples, there are some obvious errors in the BeerXML sample files downloadable
   from www.beerxml.com:
@@ -188,7 +188,7 @@
         writes out booleans in lower case.  So, in the spirit of Postel's Law, we ought to support that too.
 
         And since we're being all liberal about what we accept, let's cover off "True" and "False", just in case.
-         -->
+   -->
    <xs:simpleType name="RobustBoolean">
       <xs:restriction base="xs:string">
          <xs:enumeration value="TRUE"/>
@@ -200,11 +200,12 @@
       </xs:restriction>
    </xs:simpleType>
 
-   <!-- Some of the Brewtarget unofficial extensions to BeerXML use ISO 8601 format date fields.  These correspond to
-        standard XML date type, unless they are also fields that are allowed to be blank.   (Ideally, a null value for
-        a date field would have been represented by omiting the element altogether, but that's not how existing files
-        are encoded.)  So we need a type that represents either in ISO 8601 date or blank.
-        First define a blank... -->
+   <!-- Some of the Brewtarget/Brewken unofficial extensions to BeerXML use ISO 8601 format date fields.  These
+        correspond to standard XML date type, unless they are also fields that are allowed to be blank.   (Ideally, a
+        null value for a date field would have been represented by omiting the element altogether, but that's not how
+        existing files are encoded.)  So we need a type that represents either in ISO 8601 date or blank.
+        First define a blank...
+   -->
    <xs:simpleType name="Blank">
       <xs:restriction base="xs:string">
          <xs:enumeration value=""/>
@@ -224,7 +225,6 @@
         point number" in the standard, but this is something we may need to revisit.
    -->
 
-
    <!--
         ************************************************************************************************
         * Now begins the real substance.  *** In the following, pay attention to singular vs plural. ***
@@ -260,7 +260,15 @@
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
          <xs:element name="CATEGORY" type="xs:string"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <!-- In theory version should always be 1 (unless a new version of BeerXML is ever released, which seems
+              unlikely given that BeerJSON is supposed to supersede it).  In reality, some BeerXML files have 0 as the
+              version in a number of places.  This should not prevent us reading in the rest of the file, so we accept
+              it.  Moreover, some software, such as the Grainfather online recipe editor at
+              https://community.grainfather.com/, does not include the VERSION tag in all the places the BeerXML
+              standard says it is required.  So we also accept it not being present.
+
+              This comment applies to all the VERSION tags in this file.  -->
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="CATEGORY_NUMBER" type="xs:string"/> <!-- Despite the name, this is a string because it could be something like "8A" -->
          <xs:element name="STYLE_LETTER" type="xs:string"/>
          <xs:element name="STYLE_GUIDE" type="xs:string"/>
@@ -321,7 +329,7 @@
    <xs:complexType name="EquipmentType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="BOIL_SIZE" type="VolumeInLiters"/>
          <xs:element name="BATCH_SIZE" type="VolumeInLiters"/>
          <xs:element name="TUN_VOLUME" type="VolumeInLiters" minOccurs="0" maxOccurs="1"/>
@@ -349,9 +357,9 @@
          <xs:element name="DISPLAY_LAUTER_DEADSPACE" type="xs:string" minOccurs="0" maxOccurs="1"/>
          <xs:element name="DISPLAY_TOP_UP_KETTLE" type="xs:string" minOccurs="0" maxOccurs="1"/>
 
-         <!-- ************************************************************************************
-              *** Extra fields not included in the BeerXML 1.0 standard but used by Brewtarget ***
-              ************************************************************************************ -->
+         <!-- ********************************************************************************************
+              *** Extra fields not included in the BeerXML 1.0 standard but used by Brewtarget/Brewken ***
+              ******************************************************************************************** -->
          <xs:element name="REAL_EVAP_RATE" type="SimplePercentage" minOccurs="0" maxOccurs="1"/>
          <xs:element name="ABSORPTION" type="xs:decimal" minOccurs="0" maxOccurs="1"/>
          <xs:element name="BOILING_POINT" type="TemperatureInCelsius" minOccurs="0" maxOccurs="1"/>
@@ -370,7 +378,7 @@
    <xs:complexType name="HopType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="ALPHA" type="SimplePercentage"/>
          <xs:element name="AMOUNT" type="xs:decimal"/> <!-- In kg -->
          <xs:element name="USE">
@@ -398,9 +406,14 @@
          <xs:element name="FORM" minOccurs="0" maxOccurs="1">
             <xs:simpleType>
                <xs:restriction base="xs:string">
+                  <!-- These are supposed to be case-sensitive, but some files have them in lower case, so we accept it
+                       as it's not ambiguous -->
                   <xs:enumeration value="Pellet"/>
                   <xs:enumeration value="Plug"/>
                   <xs:enumeration value="Leaf"/>
+                  <xs:enumeration value="pellet"/>
+                  <xs:enumeration value="plug"/>
+                  <xs:enumeration value="leaf"/>
                </xs:restriction>
             </xs:simpleType>
          </xs:element>
@@ -436,7 +449,7 @@
    <xs:complexType name="FermentableType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="TYPE">
             <xs:simpleType>
                <xs:restriction base="xs:string">
@@ -474,9 +487,9 @@
          <xs:element name="INVENTORY" type="xs:string" minOccurs="0" maxOccurs="1"/>
          <xs:element name="DISPLAY_COLOR" type="xs:string" minOccurs="0" maxOccurs="1"/>
 
-         <!-- ***********************************************************************************
-              *** Extra field not included in the BeerXML 1.0 standard but used by Brewtarget ***
-              *********************************************************************************** -->
+         <!-- *******************************************************************************************
+              *** Extra field not included in the BeerXML 1.0 standard but used by Brewtarget/Brewken ***
+              ******************************************************************************************* -->
          <xs:element name="IS_MASHED" type="RobustBoolean" minOccurs="0" maxOccurs="1"/>
       </xs:all>
    </xs:complexType>
@@ -497,7 +510,7 @@
    <xs:complexType name="MiscType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="TYPE">
             <xs:simpleType>
                <xs:restriction base="xs:string">
@@ -552,7 +565,7 @@
    <xs:complexType name="YeastType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="TYPE">
             <xs:simpleType>
                <xs:restriction base="xs:string">
@@ -622,7 +635,7 @@
    <xs:complexType name="WaterType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="AMOUNT" type="VolumeInLiters"/>
          <xs:element name="CALCIUM" type="xs:decimal"/> <!-- In parts per million of Ca -->
          <xs:element name="BICARBONATE" type="xs:decimal"/> <!-- In parts per million of HCO3 -->
@@ -654,7 +667,7 @@
    <xs:complexType name="MashStepType">
       <xs:all>
          <xs:element name="NAME" type="xs:string"/> <!-- TBD whether this should be NonBlankString -->
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="TYPE">
             <xs:simpleType>
                <xs:restriction base="xs:string">
@@ -682,9 +695,9 @@
          <xs:element name="DISPLAY_STEP_TEMP" type="xs:string" minOccurs="0" maxOccurs="1"/>
          <xs:element name="DISPLAY_INFUSE_AMT" type="xs:string" minOccurs="0" maxOccurs="1"/>
 
-         <!-- ***********************************************************************************
-              *** Extra field not included in the BeerXML 1.0 standard but used by Brewtarget ***
-              *********************************************************************************** -->
+         <!-- *******************************************************************************************
+              *** Extra field not included in the BeerXML 1.0 standard but used by Brewtarget/Brewken ***
+              ******************************************************************************************* -->
          <xs:element name="DECOCTION_AMOUNT" type="VolumeInLiters" minOccurs="0" maxOccurs="1"/>
 
       </xs:all>
@@ -705,7 +718,7 @@
    <xs:complexType name="MashType">
       <xs:all>
          <xs:element name="NAME" type="xs:string"/> <!-- TBD whether this should be NonBlankString -->
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="GRAIN_TEMP" type="TemperatureInCelsius"/>
          <xs:element name="MASH_STEPS" type="MashStepsType"/>
          <xs:element name="NOTES" type="xs:string" minOccurs="0" maxOccurs="1"/>
@@ -741,7 +754,7 @@
    <xs:complexType name="InstructionType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="directions" type="xs:string"/>
          <xs:element name="hasTimer" type="RobustBoolean"/>
          <xs:element name="timervalue" type="xs:string"/> <!-- NB lowercase not camelCase. AFAICT this is a display-only value and should be blank if hasTimer is FALSE -->
@@ -763,7 +776,7 @@
         AFAICT this is the only record type that does not have a NAME field -->
    <xs:complexType name="BrewNoteType">
       <xs:all>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="ACTUAL_ABV" type="xs:decimal"/>
          <xs:element name="ATTENUATION" type="SimplePercentage"/>
          <xs:element name="BOIL_OFF" type="VolumeInLiters"/>
@@ -811,7 +824,7 @@
    <xs:complexType name="RecipeType">
       <xs:all>
          <xs:element name="NAME" type="NonBlankString"/>
-         <xs:element name="VERSION" type="xs:positiveInteger"/>
+         <xs:element name="VERSION" type="xs:nonNegativeInteger" minOccurs="0" maxOccurs="1"/>
          <xs:element name="TYPE">
             <xs:simpleType>
                <xs:restriction base="xs:string">
@@ -822,7 +835,8 @@
             </xs:simpleType>
          </xs:element>
          <xs:element name="STYLE" type="StyleType"/> <!-- NB singular not plural here -->
-         <xs:element name="EQUIPMENT" type="EquipmentType"/> <!-- NB singular not plural here -->
+         <!-- Note that Equipment is optional -->
+         <xs:element name="EQUIPMENT" type="EquipmentType" minOccurs="0" maxOccurs="1"/> <!-- NB singular not plural here -->
          <xs:element name="BREWER" type="xs:string"/>
          <xs:element name="ASST_BREWER" type="xs:string" minOccurs="0" maxOccurs="1"/>
          <xs:element name="BATCH_SIZE" type="VolumeInLiters"/>
@@ -839,7 +853,9 @@
          <xs:element name="FERMENTABLES" type="FermentablesEmptyAllowedType"/>
          <xs:element name="MISCS" type="MiscsEmptyAllowedType"/>
          <xs:element name="YEASTS" type="YeastsEmptyAllowedType"/>
-         <xs:element name="WATERS" type="WatersEmptyAllowedType"/>
+         <!-- Strictly speaking the WATERS tag is required inside a RECIPE, even though it is allowed to be empty, ie
+              to contain no WATER records.  Some software doesn't write it out though, so we make it optional. -->
+         <xs:element name="WATERS" type="WatersEmptyAllowedType" minOccurs="0" maxOccurs="1"/>
          <!-- The BeerXML 1.0 Standard defines the next field as required, but then goes on to say in its description
               that 'No Mash record is needed for “Extract” type brews'.  We'll take the description as accurate.
               As noted above for EFFICIENCY and INFUSE_AMOUNT, we ideally would include an xs:assert tag here to
diff --git a/src/model/Recipe.cpp b/src/model/Recipe.cpp
index 3a34ffa3a..2e376b827 100644
--- a/src/model/Recipe.cpp
+++ b/src/model/Recipe.cpp
@@ -2925,10 +2925,12 @@ double Recipe::ibuFromHopAddition(RecipeAdditionHop const & hopAddition) {
       .postBoilVolume_liters = this->pimpl->m_finalVolumeNoLosses_l,
       .wortGravity_sg        = m_og,
       .boilTime_minutes      = boilTime_mins,  // Seems unlikely in reality that there would be fractions of a minute
-      .coolTime_minutes          = boil->coolTime_mins(),
-      .kettleInternalDiameter_cm = equipment->kettleInternalDiameter_cm(),
-      .kettleOpeningDiameter_cm  = equipment->kettleOpeningDiameter_cm (),
+      .coolTime_minutes      = boil->coolTime_mins(),
    };
+   if (equipment) {
+      parms.kettleInternalDiameter_cm = equipment->kettleInternalDiameter_cm();
+      parms.kettleOpeningDiameter_cm  = equipment->kettleOpeningDiameter_cm ();
+   }
    if (hopAddition.isFirstWort()) {
       ibus = fwhAdjust * IbuMethods::getIbus(parms);
    } else if (hopAddition.stage() == RecipeAddition::Stage::Boil) {
diff --git a/src/serialization/xml/BeerXml.cpp b/src/serialization/xml/BeerXml.cpp
index f9741b29b..a265035a8 100755
--- a/src/serialization/xml/BeerXml.cpp
+++ b/src/serialization/xml/BeerXml.cpp
@@ -1120,9 +1120,9 @@ namespace {
       //
       // † The BeerXML 1.0 standard diverges from valid/standard XML in a few ways:
       //    • It mandates an XML Declaration (which it calls the "XML Header"), which is normally an optional part of
-      //      any UTF-8 encoded XML document.  (This is perhaps because it seems to mandate an ISO-8859-1 coding of
-      //      BeerXML files, though there is no explicit discussion of file encodings in the standard, and this seems
-      //      an unnecessary constraint to place on files.)
+      //      any UTF-8 encoded XML document.  (This is perhaps because it seems to mandate an ISO-8859-1 aka "Latin 1"
+      //      coding of BeerXML files, though there is no explicit discussion of file encodings in the standard, and
+      //      this seems an unnecessary constraint.)
       //    • It omits to specify a single root element, even though this is a required part of any valid XML document.
       //    • It uses "TRUE" and "FALSE" (ie caps) for boolean values instead of the XML standard "true" and "false"
       //      (ie lower case).
@@ -1142,6 +1142,9 @@ namespace {
       // Note here that we are assuming the on-disk format of the file is single-byte (UTF-8 or ASCII or ISO-8859-1).
       // This is a reasonably safe assumption but, in theory, we could examine the first line to verify it.
       //
+      // We further assume the first line of the file can be treated as ISO-8859-1 aka "Latin 1", but, again, this
+      // should be safe as it's just one or two tags, not user content.
+      //
       // We _could_ make "BEER_XML" some sort of constant eg:
       //    constexpr static char const * const INSERTED_ROOT_NODE_NAME = "BEER_XML";
       // but we wouldn't be able to use that constant in beerxml/v1/BeerXml.xsd, and using it in the few C++ places we
@@ -1150,7 +1153,7 @@ namespace {
       // readability over purity, and left it hard-coded, for now at least.
       //
       QByteArray documentData = inputFile.readLine();
-      QString firstLine{documentData};
+      QString firstLine{QString::fromLatin1(documentData)};
       qDebug() << Q_FUNC_INFO << "First line of " << inputFile.fileName() << " was " << firstLine;
       if (!firstLine.startsWith(QString("<?xml version="))) {
          //
@@ -1163,7 +1166,16 @@ namespace {
          userMessage << "Unexpected first line (not the XML declaration mandated by BeerXML).";
          return false;
       }
-      documentData += "<BEER_XML>\n";
+      //
+      // Some software, such as the Grainfather online recipe editor at https://community.grainfather.com/, omits to put
+      // a linebreak after the initial tag, so it will export a first line such as:
+      //    <?xml version="1.0" encoding="UTF-8" ?><RECIPES>
+      // So, rather than just append our root tag after line 1, we find the end of the first tag and insert it there.
+      // It's easier to do the insertions in QString and then overwrite the raw data we read in for the first line.
+      //
+      auto const tagEnd = firstLine.indexOf(QChar{'>'});
+      firstLine.insert(tagEnd + 1, "\n<BEER_XML>");
+      documentData = firstLine.toLatin1();
       documentData += inputFile.readAll();
       documentData += "\n</BEER_XML>";
       qDebug() << Q_FUNC_INFO << "Input file " << inputFile.fileName() << ": " << documentData.length() << " bytes";