This has been released this week and contains 2 important things I think.
1. The feeder issue in 9.1 sp1 where if you used curly brackets {} in your feeders then only the first element would feed; has been fixed.
2. There is a new function available called TM1User
e.g. =TM1User("sdata")
Should be cool for all sorts of things for tracking and helping users.
Watch out for this tech bulletin though explaining how any computer you try installing V9.1 SP2 will need to have Adobe acrobat on it in order to install successfully
http://www.applix.com/support/documentation.asp?docid=1542