I am having a variety of issues updating from V.8 to V. 9 including PHP 8.0 errors.
I have spent copious hours searching the forum and support and documentation.
I have 2 suggestions:
- A specific category for this topic and/or
- A chapter in the developer documentation on this topic.
On the subject of the documentation - I think this also urgently needs to be split for Version 9 as there are great differences in theme, block and package development.