Start with making a safety backup of your database using your DBMS, then upgrade the ITP/MDK Repository Server.
The service used by the server need not be stopped for an upgrade. The installer will stop it.
Have all users close their client sessions to prevent disruptive disconnect errors during upgrade.
Run the server installer (ITP/MDK Repository Server setup.exe) on the machine that runs ITP/MDK Repository Server.
After the installation is completed the installer can attempt to start the service used by the ITP/MDK Repository and it will notify the result.