I have searched and roamed over the forums and documentation and I have not found an answer, so asking here.
With Ubuntu 20.04 LTS “just around the corner” what is Nextcloud’s stance on supporting a new version of an OS? Is there a time period after the new OS is released that it becomes supported and then more time before it becomes the recommended OS?
I saw discussions back in Jul 2019 about NC15 and its EOL (Dec 2019) and this being an issue for people wanting to upgrade their 16.04 LTS (PHP7.0), but not wanting to use Ubuntu 18.04 LTS and miss out on the extra 2 years life of the OS that 20.04 LTS would give them.
I think the problem is the adoption that a server administrator can only install Ubuntu 16.04 LTS and then Ubuntu 20.04 LTS because oft the support time from Ubuntu 16.04 LTS till April 2021.
I think it is not possible to dist-upgrade directly from 16.04 LTS to 20.04 LTS. Normal administrators do also not reinstall all from 16.04 LTS to 20.04 LTS betweeen April 2020 and April 2021 (end of support 16.04 LTS).
If someone uses an Ubuntu 16.04 LTS - server he/she should dist-upgrade to 18.04 LTS betweeen April 2018 and April 2020 and dist-upgrade to 20.04 LTS between April 2020 and April 2021. And then there shoud no problems with apache2, mariadb, php and nextcloud versions.
Normal administrators do not cancel an ubuntu lts release because of longer support time of the older ubuntu release.
There is no special support for Linux versions. The only thing to be careful is the php version that it is officially supported. 20.04 comes with php 7.4 (?) this will be officially supported by NC 19 (next version).
For a new setup, I’d go directly with NC 19 (when it is out) and Ubuntu 20.04. For updates, you usually wait for the first point release in summer. Until then, you can already upgrade to NC 19 first (perhaps wait for the first 1-2 point releases), and then upgrade Ubuntu. However, do backups. Most of the times it works quite good, but I had a few bad surprises as well.