Will this work for version 25.615.4 of black ops 2 mp?
The current game version of Black Ops 2 is 1.0.13
25.615.4 is the playlist version, which does not affect hacks at all. No actual game code is changed when they change the playlist update. The only time that hacks have to be updated is when they do a major update and the game version changes.
But back to your original question, yes, this trainer works for the current version of the game 1.0.13
It depends on how you use it. If you use it in an active lobby or forget to close it before entering a lobby or match, then you have a greater chance of getting banned. Also if you use it every single match to gain huge amounts of XP to reach Prestige Master in a day or two, you have a greater chance of getting noticed and banned.
That being said, this trainer has been downloaded 1,650 times and less than 20 people have complained that they got banned from it. That's only a little over 1% of the total number of players who downloaded this. It's up to you. You take your chances with any hack/cheat/trainer.