i have downloaded TBB from whonix downloader (on freshly whonix 13)
the downloader shows the last version of TBB is 5.5.5 , and showed this message after i download it:-
but the latest TBB tho is 6
This is up for The Tor Project to define.
They not yet have updated the recommended TBB version file.
https://www.torproject.org/projects/torbrowser/RecommendedTBBVersions