Update release notes

release-notes/8-x.md

@@ -1,4 +1,12 @@
 # Release Notes for PROSE SDK versions 8.x
+## [Release 8.28.0](https://www.nuget.org/packages/Microsoft.ProgramSynthesis/8.28.0) - 2023/10/24
+- Microsoft.ProgramSynthesis
+  - Data.Diff is no longer included in the SDK.
+
+- Transformation.Formula:
+  - Added formula explanations exposed through the Translation.Explanation property.
+  - Major performance improvements to elapsed time during learning.
+
 ## [Release 8.27.0](https://www.nuget.org/packages/Microsoft.ProgramSynthesis/8.27.0) - 2023/09/25
 - Transformation.Formula
   - Added an interface ILocalizedStrings to pass localized strings to be used in Python translation.