This is actually an automated process. If the client encounters a new server version it will automatically download and install the correct version.
When a MeasureColor server gets updated while a client is running the client will detect the new server version and logs off the user when OK is pressed.
The display will show the update progress and will return to the login screen. You can now log in with the updated MeasureColor client.
If for some reason the automatic update might fail you can manually update the client: Adding a client workstation to a MeasureColor 17.2.xx and later server