Upgrade from 10.0.6 not working

Hello,
I’m trying to upgrade an old nextcloud 10.0.6 version installed on a Ubuntu 14.04 server.
I don’t have any information about what kind of nextcloud installation was originally performed.
I just know that I need to upgrade php from 5.5 to 5.6 or 7 to be able to upgrade to newer versions.
But when I installed php5.6, nextcloud was broken and so I did a rollback of this VM to the previous state.
I’ve read around and this seem to be related to the type of nextcloud install but I’ve found no solution yet.
Any info would be much appreciated.

How was Nextcloud broken?

you can upgrade your php with ppa . and try to upgrade nextcloud manually .

Calling the website from browser it gave an error like apcu memcache…something like this.
This happened about 10 days ago, and when this was not working I just rolled back to the previous snapshot.
I suspect that this (proxmox) container is derived from a virtualbox appliance.

Already did, and the error appeared.

I was able to find that the nextcloud server was installed from a linux turnkey appliance.
Is this kind of install not-upgradable at all ??
I’m stuck here.

Thanks

You’re going to need to provide more information if you want people to be able to help you.