Tenfourbird is unofficial build of Mozilla Thunderbird for PowerPC based Mac OS X.
Tenfourbird uses changesets of TenFourFox.
Latest version is 38.9.0.
If you find bug, please report to Forums or Ticket system.
You can check integrity of files by SHA1 hashes. It signed by OpenPGP key of t_mrc-ct[at]users.sourceforge.jp. The public key could get from here or OpenPGP Keysever.
All Langpacks have not been updated since v31.0. You can use these on Tenfourbird 31.1.0.