sogo/gnustep mysteriously adds XML-encoded UTF-8 BOM

Hello!

This is just a heads-up for fellow SOGo users and a plea to
@landry: would you mind sharing your new gnustep/sogo packages?

After upgrading to OpenBSD 7.0 with the updates to:

-sogo-5.0.1p0 web based groupware server
+sogo-5.2.0 web based groupware server
-gnustep-base-1.27.0p0 GNUstep base library
+gnustep-base-1.28.0p1 GNUstep base library

I experience a symptom of "you can create events but you cannot change
them". Clients are DAVx5 for android and caldavsynchronizer for
Outlook/Windows10. DAV access with e.g. cadaver(1) works.

While chasing the cause I soon found I'm not the first to do so, thank
you, landry@, for beeing quicker:

SOGo bug report by landry@
https://www.sogo.nu/bugs/view.php?id=5416

Gnustep bug report by landry@
https://github.com/gnustep/libs-base/issues/212

The commit landry@ reverted to get www/sogo to a working state:
https://github.com/gnustep/libs-base/commit/bd5f2909e6edc8012a0a6e44ea1402dfbe1353a4

According to the SOGo bug tracker the issue has not been acted upon,
but mind it is only two days old.

Marcus