Rated 5 out of 5 stars

Hello. What about Thunderbird 78.0 (release) compatibility?

This review is for a previous version of the add-on (4.18.1). 

working on it. Here is the first useful beta (5.0 pre 52):

https://github.com/RealRaven2000/QuickFolders/issues/8#issuecomment-673027327

Please do not upgrade until Thunderbird auto-pushes Tb 78.2 on all users - presumably mid-September. I am working with a second developer and am investing several 1000$ into updating all my commercial add-ons for Tb78 so I do have a deadline. We cannot make the 78.0 and 78,1 releases but that's okay; we need to aim for quality over rushing out an unfinished release. I have already invested $650 into the new website (github pages) - because the free server on mozdev.org died a death.
No need for a 3 star rating my friend!