Hello! I use debian and old owncloud packaged version - 8.1.12. To perform correct upgrade I need to move to 8.2.11 (and then to 9.x → 10.x), but there are no deb files for it anymore for this version…
Is there possible to upgrade from this version to maybe some old version of nextCloud and then to the last?
Or there can be unofficial instructions hot to upgrade to more newer version? I do not use 3rd party apps, only standard. Please, help!
there are owncloud docker images starting from 7.0.10 to the fresh 10.x You could migrate your owncloud to docker container, upgrade as far you need and then switch to Nextcloud according to the official guide You can still do this in docker and move later to your preferred platform. Given you have enough free space you could try migration from/to different versions so you can choose which one works best for you.
Is it enough to move mysql data and owncloud/data folders into container for this migration? May be there is an instrustion for migration?
You can use your current setup, make a backup of your data and database first. Then keep the data/ and the config/-folder, delete everything else (the code of the old version). Then unpack the code of the newer version (Older Versions - ownCloud), extract the files, fix permissions (if necessary), run php occ upgrade. There should be a more detailed description in the documentation under manual upgrade.
Problem is that you messed up the deb-stuff with your fiddeling around. Either go to manual upgrades, or you need at some point to force back the files from the packages (BACKUP!). If you want to move to Nextcloud, you can do that from oC 9.0 onwards, the later you go, the more tricky it gets (most did the conversion back then, with recent versions there are a few and the code diverged since then).