You can change your project mpr metadata using the undocumented Mendix MprTool.
This method works fine between versions with small changes!…
As the changes on model will not be downgraded, so your may expect some anomalies in cases like: lets say from 9.18 to 9.16. (9.18 has changed system models)
But, so far, its the only way that i know to change versions in Mendix.
So, Try out and do your tests carefully , as its a undocumented / unsupported method!
You don't have to download the mpr tool. Open the folder where you installed studio pro, then go to the “modeller” folder, and in there you will find mprtool.exe.