Making a route compatible with all versions of bve is not as simple as you think. BVE2 requires only RW format. Some routes have animations that won't work in BVE4 (Ex Birmingham Cross City South V3 or w/e). Some routes won't work properly in openBVE. Same concept with trains
BVE supports both RW and CSV formats. What it doesn't support, is animated files such as signals, station displays, etc which our newer routes are adapting to.
Its nothing that the original author of the route cannot do. He can make the route compatible with all versions of BVE, which the newer routes are achieving. What you will need to do if you plan to do all of this, is contact the original authors of the routes(do not ask me; their names are in the downloads section). Then you will need to know the basics of coding a BVE route before you go diving into a route file and end up destroying the coding.
BStyles