Office-Online is not locking files which causes conflicts

[AlexanderZuehr]

Describe the bug
Office Online is not locking file if I am working within office-online so that an other person is able to open them locally which is leading to conflicts of the file because two persons are working on it at the same time without knowing it.

To Reproduce
Steps to reproduce the behavior:

1. Person A opens a file with office-online and works with it.
2. Person B opens the same file locally (synced with nextcloud client) and also works with it
3. Person B gets conflicts after saving because there was no warning that the file is already used somewhere else
4. Person A doesn't even notice something went wrong

Expected behavior
If Person A is working on the file within office-online it should be locked for all other user and programs except office-online itself because of the working together feature.

Client details:

• Nextcloud-Client 3.12.3

Nextcloud version:

• Nextcloud 27.1.7

Version of Office Online server

• Office Online integration 2.1.0