Karaluxer v3 is now roughly feature complete. As mentioned before v3 will be the last major rewrite of the program.
Duet support still needs some improvement, but there are options that will help with making automatic duets on some songs (very dependent on how the subtitle file is structured).
There's some support for special characters in this release, however, I'd still recommend manually checking songs work with your Karaoke program of choice (Especially if you're an Anisoc member and trying to submit a song for Karaoke).
These releases are likely to only be made when there are significant changes, so I'd recommend grabbing the automatically compiled executable for the latest commit from the actions page or using the python script.