Trying to calculate replaygain on MP3 files fails with the processing appearing to get stuck. This is due to an internal change which broke how the internal setup of the action is done & requires a new build to resolve it. Additionally specific to the x64 build it is possible for the "calculating x%" to not update as expected when dealing with some larger files (not MP3 specific).
The pull mode with the notsoyasapi output plug-in seemingly hasn't ever properly worked & trying to use it will break playback. As the default push mode works it's best to stick to that.
The provided ASIO output plug-in & possibly the WASAPI output plug-in for some may not be working - this still needs to be investigated to replicate & then resolve where possible.
The shuffle table may not act as expected & is still to be finished being re-worked. This was also present in the 216xx builds & possibly 215xx.
SNSF sets won't play correctly or at all which is still to be investigated fully.
Smart App Control with Windows 11 can either cause the first run after an install to take an age or it'll just randomly block dlls from being loaded (e.g. image.w5s) which depending on what's blocked will either prevent WACUP from being able to complete loading or it'll be somewhat hobbled often until restarting & then everything will usually be allowed to load. I don't like this!