It is not a brand new version the mobile game though, SNK just released a free version of the same King of Fighters-A 2012 (F) for Android users that has been around for a couple of years now with an original price of $3. If you search it on the Google Play you will still see the paid version sitting side by side with the free version, so I guess you just need to look for the one that says (F) at the end of the title to know which is free.
There are almost no difference that can be found between the paid and the free version, but according to a post on Phandroid, the total number of playable characters has been cut down from 34 to 32. The article also said that they think Kyo and Iori are the ones being removed from the paid version. If you haven't tried the game yet on your Android device, you can now go ahead and visit Google Play and give it a try while it is free as we do not know how long this thing is going to last.