add release notes for 3.9.x

JamesClonk · JamesClonk · commit a593e511bb6f · 2024-02-15T10:41:41.000+01:00
diff --git a/release-notes.html.md.erb b/release-notes.html.md.erb
@@ -2,6 +2,14 @@
 title: APC Release Notes
 ---
 
+## <a id='3.9.x'></a> 3.9.x
+
+Release date: 15.02.2024
+
+#### OS update only
+This platform release is based on the previous release and contains an OS (stemcell) update only.
+
+
 ## <a id='3.7.x'></a> 3.7.x
 
 Release date: 20.12.2023
