In most cases your Android TV should automatically update installed apps.
If you need to manually update the ATHLIV TV App;
1. Open the Google Play Store app on the TV
2. Navigate to the initials icon in the top right hand corner and press OK on the remote
3. Select Manage apps & games and press OK on the remote
4. Select Update all and press OK on the remote
5. Press the HOME button on the remote to return to the homepage and launch the ATHLIV TV App