Good news, I have tested the core on PHP 8.3 and I didn't get any errors in the tests that I could do. I do have problems with the content module, it gives me a white page once I set my server to PHP 8.3, so there is some incompatibility there.

I am in the works of building a new admin theme based on the Bulma (bulma.io) CSS framework. First I want to see how far I can get by using the standard Bulma layout and colours.

It is coming along nicely, and one of the goals is to have a completely mobile experience as well.

I have the core in its latest code version working on PHP 8.3 since a few hours, and no issues until now that are related to the core.

The big challenge will be the modules : I've been able to test with imBlogging and imTagging, but the content module for example doesn't even install, and neither does iForum2.

Feedback for ImpressCMS 2.0 Beta 1 : put it here