I would like to know if during the process of manual update (using occ command) the files in data directory are modified. So, for example, if I try an update and later I want to revert the installation to an old version (restoring the database and Web folder) I will have problems because of data files modified during the update. The question concerns versions of NextCloud from 12 to 17.
I’m not sure about the server-side encryption, without it, the upgrade process should not touch files in the data folder. Reverting to a previous situation is kind of the last thing if a new version does not work for your and ideally should be done as quick as possible. Revert after a couple of days is a bad idea (your data and database will be out of sync).
If I am not sure, and want to try new things, I tend to use a test-setup for these purposes. You can check things out, try if they break etc. Especially if you want to make sure all your apps are working and you want to use the latest version (e.g. like NC 17 which was released recently). NC 15 (still supported until end of this year) and NC16 are more stable and should not have major problems.
Keep in mind that the recommended way to migrate is not to skip major versions.
This means the correct upgrade path is NC 12 > 13 > 14 > 15 > 16 > 17 as described here
Thanks to all for the answers.
No, we don’t have encryption.
Yes, I understand that reverting to the last version after some days of working under the new one is a bad idea
The question was about reverting after a test stage.
And no, we never skip major versions during update. I just asked if ALL versions have the same behavior.