Update release notes wrt #1039

Author: k163377

release-notes/CREDITS-2.x

@@ -15,7 +15,12 @@ Authors:
 
 Contributors:
 
-# 2.20.0 (not yet released)
+# 2.21.0 (not yet released)
+
+WrongWrong (@k163377)
+* #1039: Update settings for 2.20
+
+# 2.20.0 (28-Aug-2025)
 
 WrongWrong (@k163377)
 * #1025: Deprecate MissingKotlinParameterException and replace with new exception

release-notes/VERSION-2.x

@@ -18,7 +18,7 @@ Co-maintainers:
 
 2.21.0 (not yet released)
 
-No changes since 2.20
+#1039: Kotlin has been upgraded to 2.1.x.
 
 2.20.0 (28-Aug-2025)