Drop support for PHP 7.4 and 8.0

[blackcoder87]

This is an early reminder for dropping support of older PHP versions. This should be planned some time in advance.
It is probably a good idea to announce the removal of support for older versions early like it was done with the removal of support for earlier versions.

PHP 7.4 and 8.0 are both no longer officially supported.
PHP 8.1 is supported until 31 Dec 2025.
http://php.net/supported-versions.php

Debian 11 with PHP 7.4 is supported until June 30th, 2026.
Debian 12 with PHP 8.2 is supported until June 30th, 2028.
https://wiki.debian.org/LTS

There is the Expanded Security Maintenance (ESM) program for Ubuntu. It provides support for up to 10 years.

For each Ubuntu LTS release, Canonical maintains the Base Packages and provides security updates, including kernel livepatching, for a period of ten years. The lifecycle consists of an initial five-year maintenance period, during which maintenance updates are publicly available without an Ubuntu Advantage Subscription, and five years of Expanded Security Maintenance (ESM). The full lifecycle is available with an Ubuntu Advantage subscription or a free personal subscription.

See also: https://ubuntu.com/security/esm

Trying to support old PHP versions for that long would probably cause us problems with various packages we use. So we should only try to adhere to the normal support time in case of Ubuntu (and generally). See below.

Ubuntu 20.04 is using PHP 7.4 and is supported until April 2025.
Ubuntu 22.04 is using PHP 8.1 and is supported until April 2027.
Ubuntu 24.04 is using PHP 8.3 and is supported until April 2029.
https://ubuntu.com/about/release-cycle
https://wiki.ubuntuusers.de/PHP/
https://wiki.ubuntuusers.de/Long_Term_Support/

Fedora 36 with PHP 8.1 is supported until 2023-05-16.
Fedore 37 with PHP 8.2 is supported until 2023-12-05.
Fedore 38 with PHP 8.2 is supported until 2024-05-14.
Fedore 39 with PHP 8.2 is supported until 2024-11-12.
https://packages.fedoraproject.org/pkgs/php/php/
https://en.wikipedia.org/wiki/Fedora_Linux#Releases

OpenSUSE 15.4 with PHP 8.1 is supported until 2023-11-30.
OpenSUSE Tumbleweed is currently on PHP 8.1. It's a rolling release.
https://en.opensuse.org/openSUSE:Roadmap#Schedule_for_openSUSE_Leap_15.4
https://en.wikipedia.org/wiki/OpenSUSE#Releases