in resourses to this game download MOST RECENT DOWNPATCHER, then open regfix folder and run Enable, then open Patcher folder, check the box - show all patches, choose game folder (steamapps/common/borderlands2), and choose 200 to 110 (or whatever version u want), to check is this work in game open matchmaking - match browser and the game version will be displayed in the lower right corner

check in discord channel in bl2 resources, its called info tracker