I too am wondering this! The phone came out the day before I was supposed to order my Redmi 3 and the bump in RAM and storage are much appreciated. Also the fingerprint scanner is nice for quick unlocking (I currently don't use a screenlock cause I cba with it every time I use the phone, but this also means it sometimes unlocks in my pocket), but does this require the ROM to be different, or is firm-/software for that built into Android itself (so basically any ROM will work with the scanner)?