Special backup file while ovewriting a v4 game with v5

It would be helpful if Visionaire 5 generates a special backup before overwriting a v4 file. For example filename.ved.bak4. The problem is, if you save 2 times with Visionaire 5 after loading a v4 game, then the v4 file is lost forever...

If you're that concerned you can downgrade a v5 file by removing all v5 fields, they are listed in the viseditor.log after you tried to load it.