Problems with OnlyOffice & Community Document Server (file versions)

Hi folks,

in our cooperative society, we use Nextcloud Hub hosted by manitu.de.
We installed OnlyOffice (OO) & Document Community Server (DCS) from the Nextcloud app store.

  1. Right now, documents may not be edited and aren’t recognized according to their type (e.g. docx) while OO is enabled.
  2. Before, we were able to open and edit documents, without versioning/version history, though.

Any ideas how to solve the issues?

Nextcloud (Hub) 25.0.2
Version of ONLYOFFICE connector 7.6.8
Document Community Server 0.1.13

OK, whatever reason for, (after some dis- and enabling) files may be edited again, version control and file type preview are not working, however.