Upgrade php7 to php8

[susejunky]

@xlarva

the end goal here is to do the upgrade of php as seamless as possible since we want to keep the server online as much as possible and avoid possible incompatibilities with apache2

If you migrate a production server then the most important thing to do before you move from php7 to php8 is to make sure that all your current php code will execute correctly under php8. Once you have done that you can install php8 on your server.

I moved my openSUSE Tumbleweed installation from php7 to php8 some months ago. Here is how I proceeded:

1. take a list of all currently installed php7packages
2. install php8 (this should remove php7)
3. install all php8 modules needed (see list of php7 modules)
4. make sure apache2-mod_php8 is installed
5. check (and if necessary adjust) /etc/sysconfig/apache2
6. reboot system