Official builds of Firefox version 3.6.18 and Thunderbird version 3.1.11
have been released (dated 6/19/2011, but made available a few days
later). As with previous 3.x Firefox builds, there are some known
issues (particularly with printing); Java support is also no longer
available. There is a build of Lightning for Thunderbird 3.1.x, which adds calendar support. See my Warpzilla tips page for more information.
Source. OS/2 Warp News and Rumors