3.11. MFC 4.1
The most important thing about this release is that it is the last release that supports Win32s. There are tons of MFC developers stuck on this release, so if you see someone posting that they are using MFC 4.1, that is probably why. This fixed many of the 4.0 bugs and added some new Internet features.
%%TODO - get the date and a more comprehensive list of what was new. Can't remember if ISAPI was in here yet, but I'm pretty sure it had the "sweeper" stuff - HTTP, gopher and ftp classes.