I’m not entirely sure what you mean. Unsupported versions of what?
The tag on your topic says world edit. World Edit is a mod (it might also be a plugin, I’m not sure). If you want to use mods, you’ll have to select forge or fabric (with the Minecraft version you want) as your server version. Then, when you upload mods, you’ll have to make sure to upload the correct version of the mod as well. Minecraft (and the server) will crash if the version of the game and the version the mod needs don’t match up (such as, the Minecraft version is 1.18, while the mod needs 1.17). You could probably find WorldEdit on Curseforge or some other mod site. (If you already knew this, I’m sorry for wasting your time)
If that’s not what you meant, then you’ll have to clarify. Is your server just randomly saying this? If so, have you made any edits to your server’s files (or something along those lines)? Are you trying to have a snapshot as your server’s version? If you’re trying to get WorldEdit as a plugin, I’m afraid I’m inexperienced with those, and probably won’t be able to help.