What is a compatibility version of a map?

Some popular maps on CS:GO have compatibility versions. I am wondering why a map would need compatibility versions whatsoever? What does it mean to need a compatibility version, and what makes it any different from a normal map? I have a very bad computer but I can still run CS:GO on low settings at a reasonable framerate. What would make a compatibility version any different? Would it run faster than the normal iteration of the map?

Solution 1:

These compatibility versions are older versions of official matchmaking maps. They enable the correct playback of recorded match demos. Any changes on a map can make demos useless, as boxes or barrels are for example slightly moved.