I’m currently running OC 9.1 on Wheezy, so I’m at the end of the line for both O/S support and supported OC upgrades. I would like to move it over to Ubuntu Server 18.04 and get it upgraded to the latest. I see some very good install guides and in-place upgrade guides, but I need something for moving between distros/servers.
I’m very comfortable with Linux administration, I supposed I could install the same version on an 18.04 system and dump/reload MariaDB, and copy the www directory over, but there are always gotchas in big complex systems like these, so I figured it was better to ask and see what HowTo’s are available. If it involves an upgrade to OC 10, all the better.
If you are also comfortable with docker, you could think about migrating to a docker instance. Docker images are available back to version 9.0.0. Once you have migrated you should be able to easily swap out the underlying OS of your docker0 (docker host) and upgrade to the latest ownCloud docker image.
I know this is not everyone’s favorite, but I would recommend to consider it carefully.
I was hoping to get ownCloud to 18.04 in one move and continue upgrading it from there, but 9.1 only goes up to Ubuntu 17.04, and Wheezy only upgrades as far as 9.1. It looks like I’ll have to migrate it twice, or upgrade an O/S, unless someone has another idea.
Where are you getting these restrictions from? Because I have to disagree with them.
If you can install the correct PHP version for the ownCloud version, you should be able to run it.
And with the PHP PPA from Ondřej Surý you can even install PHP 5.6 on the latest Ubuntu.
So I would suggest the following:
Set up an Ubuntu 18.04 (or 19.10 whatever you prefer [both are just a single upgrade to the next LTS version])
Install LAMP stack on there with PHP 5.6
Migrate your existing ownCloud installation there
Upgrade ownCloud and PHP on the new machine.
Step 4 might be several steps, where you first have to upgrade ownCloud, then PHP and then ownCloud again. @tom42 has already described how to download older versions of ownCloud.