In #40389 the decision was made to require PHP 8.0 as minimum for the next Symfony major, but not all information given was correct. That’s why I propose to lower the minimal language level to 7.4.
What is wrong with the information in the preceding RFC?
PHP 7.4 is currently bundled by the stable and LTS releases of Debian and Ubuntu.
This is (unfortunately) not true for Debian.
Stable Debian (buster/10) only packages 7.3 by default, and the next stable release (bullseye/11, expected somewhere in the second quarter of this year) will only package 7.4: they deemed the transition to 8.0 too large, too breaking and too late. That means that 8.0 (maybe 8.1 by that time?) will only be packaged with the release of Sid, which can be expected in the second quarter of 2023 (looking at the release history).
This is relevant Debian thread: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=976811
The PHP packages and Debian versions:
This means that choosing PHP 8.0 for Symfony 6 will close the door for many stable (and thus maintained) Debian users for at least 1.5 years.
The latest LTS of Ubuntu ships with PHP 7.4, so that is true. But that also means that an LTS with PHP 8.0 cannot be expected before 2022.
This will have less impact compared to Debian, but you can still assume that users won’t be able to upgrade because they only have access to LTS versions of Ubuntu (of which the installation can postponed by whomever is managing the environment…)
In conclusion, bumping the minimum version to 8.0 might be a bit premature. It will restrict a (possibly large) group of users from upgrading to Symfony 6.0, which has (or at least, not for me) never has been blocked by an LTS OS not having the minimum required PHP version.
Note that all this only holds when you cannot (or do not want to) install a custom package repository such as https://deb.sury.org/.
As a final note: I’m just opening this to allow the RFC for reconsideration based on this information. Whether or not this changes anything is up to you