Update 5 Feb 2012: Version 10.0, from the Ubuntu PPA, is now in the main testing repo. 8.5 build successful on 32-bit, so will finish that up.
Update 31 Dev. 2011: version 9.0, from the Ubuntu PPA, is now in main testing repos.
Update 15 nov 2011: version 8.0, rebuilt from Ubuntu Precise sources, is now available in the main test repo.
Update: 12 Sept 2011: Thunderbird 6.0.2 in now in the testing CR. Please let us know how it installs and performs. This version uses the system nss libraries, so that should be the latest version, too.
Thunderbird 5.0, rebuilt from the Ubuntu source, is now available in the 32 and 64 bit main testing repository. It may take a few days for the Debian Icedove version to show up, but we'll add that too so there's a choice. Please let us know how this version is working if you give it a try--thanks!
Just FYI, Mozilla completely jumped any version 4 for this program, apparently matching the Firefox release number.
thunderbird - 5.0+build1+nobinonly-0mcr110+1
Architecture: 32bit and 64bit
Thunderbird is a full-featured email, RSS and newsgroup client that makes
emailing safer, faster and easier than ever before. It supports different mail
accounts (POP, IMAP, Gmail), has a simple mail account setup wizard, one-
click address book, tabbed interface, an integrated learning spam filter,
advanced search and indexing capabilities, and offers easy organization
of mails with tagging and virtual folders. It also features unrivalled