I have a RepRepGuru Prusa i3 V2, and they provide a download of Marlin firmware on their site. Can I look at the code and determine what version they used? Which file is it in? It has a copyright date of 2016 in it, so I feel pretty sure it isn't close to 1.1.8.
Should I consider upgrading for stability and features? Can I just diff the configuration.h file and move the differences into the newest version?