Merge branch 'staging' into nightly

data/conf/sogo/sogo.conf

@@ -16,6 +16,9 @@
     SOGoFoldersSendEMailNotifications = YES;
     SOGoForwardEnabled = YES;
 
+    // Fixes "MODIFICATION_FAILED" error (HTTP 412) in Clients when accepting invitations from external services
+    SOGoDisableOrganizerEventCheck = YES;
+
     // Option to set Users as admin to globally manage calendar permissions etc. Disabled by default
     // SOGoSuperUsernames = ("moo@example.com");