I'm using the modpack right, but i did add some mods and for some reason the modpack doesn't start with the current version of Crafttweaker of the modpack, but it will work with the most recent version. The question that i have is, why don't you guys didn't updated the crafttweaker on the modpack? I'm asking because i'm afraid of breaking something by updating the Crafttweaker.

We're not updating because CraftTweaker changed how NBT is handled in later updates, iirc :)