I found this work-in-progress Godot 4.0 Migration/Upgrade guide:
This document represents the beginning of an upgrade or migration document for GDScript 4.0 and Godot 4.0. I'm focusing on 2D at the moment as I'm upgrading a 2D game, but will hopefully have more to add for 3D afterward.
https://gist.github.com/WolfgangSenff/168cb0cbd486c8c9cd507f232165b976