The GOG version has the latest official patch. What it doesn't have and you will most certainly want to get is Greyface's patch.

https://sites.google.com/site/sergroj/mm

I'm asking because grey's patch disable music and despite any *.ini configuration I tried music will not start again. So basically I want to keep music wich is really nice. The only bug I don't want is the bug that prevent Master Chain Armor or Master Plate Armor to remove slowdown from weapon shots. Is that bug already removed in latest official patch? Other bug fixes are nice but I can live with them =).

Looking at readme.txt there's no mention of that bug fix, but also in grey's patch no one tell anything about that bug. I just need some disambiguation.

Do you have the music mp3 files placed in the right folder? Do you have the .ini file from Greyface's patch properly set up to play the mp3's?

I can't offer many specifics, but those would be some things to check.

Yeah I checked all and all related topics in the forum, i tried everything, the patch just didn't worked ^^. I retried again just to be sure (backupped saved games)

But that's not a problem the game is very fun also without the patch (most of fixes are just details, and anyway I prefer left/right arrow for turning camera instead of mouse). The only thing is that I spent a bit time looking how to balance at best the party, and weapon cool down time (the formula can be found on several websites) is part of that balancing. But unluckily I can't understand in wich patch (official 1.2 or greyface) is that fixed. The only mention of the bug is in those sites (but they didn't tell in wich patch is fixed)