This PDF gives you the status of BMW software updates:
BMW I-Level Versions
The latest for your car would be E89x-16-07-505, which comes with "ISTA P3.59.2" otherwise known as "SP Daten 59.2".
Once you have those software update files you can then just use WinKFP to flash the latest module updates.
There is a handy tool available elsewhere on the internet called "ECU Finder" which will give you the latest ZB numbers. You can then look at the 0da and 0pa files and see if they are recent.