@Ironbelly - ooh, map files are bound to be a lot more difficult because there’s usually blueprints in the map files too. You’d also have to make sure you re-build all blueprints when you do this though so it’s likely to be a much bigger headache though still technically possible. Either that or leave out the blueprints when you copy the map data. The easiest way to re-build the blueprints is to open them in the new engine version and select all and copy and then paste into a text file before pasting into a blueprint of the same type and name in the old project. This will re-create all of the nodes, but then you’ll have to go through all of the variables and right click and create them. All in all, it’s a lot more painful of a process.
You might be able to have two projects open at once - the newer version and the old one - and after you finish getting all of the assets functioning in the old version, you could try to open the map from the new version and then select all and copy from there and then open the old project, create a new empty map and hit paste. You’d just have to be sure that you’re not selecting any objects in the map that don’t exist in the old version of the engine to avoid crashes.
Again, this is just theory but it should work as you’re just getting references to actors and their transform data in the map file when you select all and copy. Definitely save all of the assets in the older project once you’ve finished re-building them before you paste in the map.