How to upgrade from Nextcloud 9 (on Ubuntu 14.04) to Nextcloud 12 (On Ubuntu 16.04/17.04) - on Digital Ocean

I have tried to upgrade in the past but the process gets confusing and it hasn’t worked so far.

I don’t want to install from scratch as migration would be a bit of a pain. What are the steps I need to take?

Is this just a virtual server or did they create their own app? If it is a plain server with just Nextcloud installed, it should work similar like the upgrade description in the docs (the manual is probably the most secure one):
https://docs.nextcloud.com/server/11/admin_manual/maintenance/manual_upgrade.html

It makes sense to use Ubuntu 16.04 (php7 support, better caching packages). I would migrate your setup to Ubuntu 16.04 first, then run the upgrades from NC 9 to 10 to 11 to 12.

Don’t forget to make backups before, there is no downgrade or other way back!

Sorry for the delayed response. I did a fresh install as they’ve now provided a 1-Click install for Nextcloud/Owncloud.

I’d tried upgrading manually in the past, but there would always be issues preventing Nextcloud from starting, and it would have been too messy anyway.

With normal Ubuntu/Debian-setups, for me the manual updates work very good (for people with full system access) and even the feedback here is very positive (though the procedure is a bit complicated).

The new updater app is getting better and better.

Yeah the updater worked quite smoothly once I set up a fresh install. The problem I had before was that I’d set up an owncloud instance, then migrated to Nextcloud, but then couldn’t get Nextcloud to upgrade smoothly from there.

With a fresh install, I was able to install NC 12 with no issues.