This was probably very stupid of me, but the other day I was looking through the packages that came up when I ran slackpkg clean-system, and I saw there was a "php8-8.1.0" there.

Thought that was strange, so I went to look at the php version 8 packages and saw that they seem to be in extra/ and are split into 80 and 81. So, I removed the old php8 package and installed the 81 from extra. Didn't think much of it.

Today, MediaWiki doesn't work, claiming that I'm missing the mbstring, ctype, iconv and intl modules. Except I'm not. They're all enabled in etc/php.ini. I do still have php7 installed - could it be that the two versions are clashing?

EDIT: Entirely stupidity on my part. Apparently MediaWiki is very unreliable with PHP 8. Removing php81 and reinstalling php7 worked. Only problem now is that I don't know why I had php8 installed in the first place and why it was working with them both before. Hopefully removing it hasn't broken anything else...

It seems they support php 8 from version 1.39
https://www.mediawiki.org/wiki/Compatibility

I think php7 will be removed soon as it reached eol on November 28th

1 members found this post helpful.

Ah, good to know. Seems I'm a few versions behind, I'd probably better upgrade soon. Thanks!