What is the best s9 firmware for BISS?

[kondor10001]

My faithfull S9 is going to my brother in law. Although he does not bother with CS at all he is into...

multisat
FTA
BISS keys
softcam and all that sort of stuff.

With that in mind, have any of you got a preference to a certain firmware update for this?

At the moment it has a Sept 2011 firmware on it.

[slugworth]

3-25

I could only get the 3-25 or 4-4 firmware to work for biss on my provider.Firmware after that wouldn't work.If you look at the files from that era,they were even named with a different format,like they changed coders after that time.