The downgrade process isn’t exactly the smoothest:
- Make (or have on hand already) a gateway backup.
- Run the uninstaller.
- Run the installer for the version you want to downgrade to.
Ideally you have a gateway backup taken from the version you want to revert to since we don’t promise forward-compatibility, but in this case I’m not sure if anything will prevent a 7.5.10 backup from being restored onto 7.5.4 if you don’t have one already.