Set version to 2.3.1, using Harchardware 2.3.1.

pom.xml

@@ -7,7 +7,7 @@
     <groupId>org.harctoolbox</groupId>
     <artifactId>IrScrutinizer</artifactId>
     <packaging>jar</packaging>
-    <version>2.3.1-SNAPSHOT</version>
+    <version>2.3.1</version>
     <name>${project.artifactId}</name>
     <licenses>
         <license>
@@ -33,7 +33,7 @@
         <IrpTransmogrifier.version>1.2.10</IrpTransmogrifier.version>
         <Girr.version>2.2.10</Girr.version>
         <Jirc.version>2.2.10</Jirc.version>
-        <HarcHardware.version>2.3.1-SNAPSHOT</HarcHardware.version>
+        <HarcHardware.version>2.3.1</HarcHardware.version>
     </properties>
 
     <profiles>

src/main/doc/IrScrutinizer.releasenotes.txt

@@ -1,16 +1,21 @@
 Release notes for IrScrutinizer, including IrpMaster/IrpTransmogrifier,
 Girr, HardHardware, DevSlashLirc, and Jirc.
 
-The gaps in release number sequence are due to keeping version numbers
-(after the first digit) equal to IrpTransmogrifier.
-
 The notation #n refers to issues number n at
 https://github.com/bengtmartensson/IrScrutinizer/issues
 ==============================================================================
-Version 2.3.1, released 202x-yy-zz.
-
+Version 2.3.1, released 2021-07-04.
+
+* If possible, use xdg-open instead of java.awt.Desktop. #433.
+* Add basis 4 option to the analyzer. #432.
+* Replace IRDB data base by RemoteLocator- #429.
+* Girr importer now imports also Remotes, CommandSets and Commands. #420
+* Misc bugfixes (#403, #407, #412, #414, #417, #421, #430).
+* interpretString: Robustness fix. #407.
 * Remove RemoteMaster import and export. #400.
 * Say "Render" instead of "Generate". #402.
+* Arduino export issues: #414.
+* Support HTML in help popups. Resolves #159.
 
 ==============================================================================
 Version 2.3.0, released 2020-09-25.