Make sure you are logged into the panel with an account authorized to use the Update App action. For this process you need the permission. You can find roles permissions here.
Go to the Devices tab and select the device you want to update.
Go into the Actions tab. Click App Version
Type the version and base version¹ you want. Press save. (Recommended 4.4.3 and higher) ²
After that your device will reboot.³
Notes :
¹ We recommend writing the same version for "version" and "base version".
² We do not recommend downgrading your OMMA App.
³ If your device is windows, the desktop may appear during the update. It is not a problem as it is part of the update process.