Updating from Nextcloud 15.x to 16.x issues due to PHP 7.0 — it requires PHP 7.1 or newer.
There's a message when you execute the updater on nextcloud to bring you to version 16 of nextcloud. It dumps out some dorky message about php7.0 but doesn't actually tell you unless you click the link it dumps. If you do it takes you to some page where they claim php7.0 is insecure and they give you a timeframe where you need to complete an upgrade from something like 7.0 to 7.2 or 7.3 and if you don't then it's your fault for running an insecure version of PHP 7.0 The problem is that updating from 7.0 to some other version is more than just updating to 7.2 or 7.3. You have all sorts of dependencies that also need to be updated. Even though 7.2 or 7.3 gets installed properly…