Will this affect Thunderbird or is it time
to hunt for an alternative?
The change will effect all Mozilla-based apps, including Firefox, SeaMonkey and Thunderbird. Plus, developers are in the process of removing the now dead-support code for Windows 2000 from Gecko since MSVC 2010 is incompatible with Win2k.
more specifically, Thunderbird 13 and Seamonkey 2.10.x will start using MSVC 2010 code, which will officially drop win2k & pre-XPSP2 support.
Thank you for telling me. I don't even know if SeaMonkey 2.10 will be renamed SeaMonkey 3.0 due to the use of MSVC 2010 code once it hits beta. MSVC 2010 will also drop support for Windows Server 2003 RTM as well.