Update release-notes for 3.27.x

Author: renelehmann

release-notes.html.md.erb

@@ -2,6 +2,15 @@
 title: APC Release Notes
 ---
 
+## <a id='3.27.x'></a> 3.27.x
+
+Release date: 21.08.2025
+
+#### OS update only
+This platform release is based on the previous release and contains an OS (stemcell) update only.
+
+
+
 ## <a id='3.26.x'></a> 3.26.x
 
 Release date: 07.08.2025
@@ -45,6 +54,7 @@ Release date: 01.07.2025
 This platform release is based on the previous release and contains an OS (stemcell) update only.
 
 
+
 ## <a id='3.24.x'></a> 3.24.x
 
 Release date: 06.06.2025