If you're using texture mods and no scripts mods, you don't need this file. Even if you have no script compilation errors, you probably still need it, as 1.30 mods might override 1.31GOTY specific changes you might want to keep. Players who have 1.31GOTY version of the game and are using 1.30 version mods.
At least until we get official answer from CDPR whether or not we get unified patch for all game versions. So here are some explanations, instructions and files to resolve the problem without a need to duplicate each and every mod. The problem is - there is no "latest patch" and many of the modmakers do not own 1.31GOTY version. Since currently we have players (and modmakers) with two different versions of the game - 1.30 (primarily Steam) and 1.31GOTY (GOG GOTY) - there are many reports of compatibility problems as well as requests for mod updates "to the latest patch". DO NOT combine both solutions, as it will result in even more merging problems in Script Merger! Uninstall instructions for this file can be found at the bottom of the page. Update: another solution is now recommended to resolve different game versions problem - Unification patch for 1.31 and 1.31GOTY game versions.