Official builds of Firefox version 3.6.13 and Thunderbird version 3.1.7
have been released (dated 12/9/2010, but released on 12/12/2010). 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