PHP 8 upgrade

On my web sites under the update report I find

PHP version should be at least 8.0.0. Before updating to PHP 8, use $ composer why-not php:8 to check if any projects need updating for compatibility. Also check custom projects manually.

But What does it means to use $composer why-not php ? or better How/where can I use it ?


Hi Elena

Can you please confirm which website you are checking? You should have received a link directly to a PHP 8.1 preview website (the .webtest domain). If you browse around on this website, and everything looks OK, then you are good to go. What matters is that you check (both as an anonymous and authenticated user) various pieces of content to ensure that each type of content used on your website continues to look correct. If you are just relying on what is included in the CERN Drupal Distribution, you are most likely all good.


Dear Joachim
the site is
I got the PHP8 webtest site but it is very hard to check all compatibilities specially when you do not know what you are looking for …
so I was hoping that this command was pointing the finger to the incompatibilities to help me to understand where the problems can come from …
So asking differently : there is a way to know if any of the local module is PHP8 incompatible ?

Dear Elena

If you have received your PHP 8.1 version, all you need to do is to browse through that website and confirm that things work and look the way they are supposed to. It is only in the event that things do not look correct that you have to go through the modules you have installed and confirm that they are indeed compatible. We have tried to make this process as easy as possible, so if everything looks correct on the PHP 8.1 version, no further action from you is necessary. We just need you to browse through your website and check; we need you to do this because we do not know how things are supposed to look and behave.