Upgrading Android version of previous mobile model to the new model

[AC Question]

Well... I own a galaxy s3 mini VE gt-i8200 which has android jelly bean 4.2.2 and none of the other custom roms are available.......
I've checked in for its older version gt-i8190....it has the latest custom rom 5.1.1.......
So... I want to ask what would be the consequences of installing it on my gt-i8200.......
Please please..... Help me!!