T-Mobile Austria gets the first official Android 4.0.3 Ice Cream Sandwich for Samsung Galaxy S2 GT-I9100 among other T-Mobile network in Europe. The new ICS 4 firmware build number I9100BOLPD. Other T-Mobile network like in Croatia, Czech Republic, Greece, Germany, Macedonia, Nederlands and UK may possibly follow soon. But if you want to upgrade now, you can use the I9100BOLPD stock ROM, this may work on all T-Mobile carrier in Europe, for it has a default apps and settings for T-Mobile carriers only.
T-Mobile - Austria
Model: Samsung Galaxy S II GT-I9100
Product Code: GT-I9100LKAMAX
Latest firmware: I9100BOLPD/I9100MAXLP5/I9100BOLP5/I9100BOLPD
Version: Android 4.0.3 Ice Cream Sandwich
Firmware info: PDA: I9100BOLPD | PHONE: I9100BOLP5 | CSC: I9100MAXLP5
Build/released: March 28, 2012 - April 06, 2012