Rated 5 out of 5 stars

As a user of the free version of QuickFolders for a while now I have come to depend on it as an essential aid to navigating the hundreds of folders I have. For my personal email account I had for years (since 1995) been using the Forté Agent email client which had been excellent. However, sadly, there has been no update since 2014 which has made it not so useful anymore (especially with its poor HTML support).
Therefore, I made the effort to move my main account to Thunderbird, which was extremely time consuming as there was no bulk export function meaning that the messages in each of the many folders had to be selected and then saved as a raw "UNIX message text file" which could then be imported into Thunderbird. Having completed the move, I am now enjoying using TB with the added functionality provided by Quickfolders.
Axel deserves a *lot* of credit for keeping the Quickfolders add-on viable so I have taken up his 2021 Easter offer of a half-price sale for a one year registration and I'm pleased I have.
Quickfolders receives a HIGHLY RECOMMENDED from me.

This review is for a previous version of the add-on (5.4.1).