8.2.5.1 will be released soon. (it's already on the Aruba Support Portal, it'll appear in MNP in about 2 weeks).
The release notes goes through both upgrade scenarios.
For upgrades prior to 8.2.4:
Upgrade from AirWave 8.2.3.1 or Earlier Versions
If you upgrade from AirWave 8.2.3.1 or earlier, you will no longer have root user access to the Linux shell after
the upgrade to AirWave 8.2.5.1, and your system will be converted to use the new AMP CLI. For information
about using the AMP CLI, see the AirWave 8.2.5.1 User Guide.
Follow these steps to upgrade from AirWave 8.2.3.1 or earlier:
1. Log in to the AirWave server as the root user.
2. Run the upgrade utility:
#start_amp_upgrade -v 8.2.5.1
The upgrade utility looks for the local upgrade package.
After the download completes, the following message appears while the software compiles:
Validating the upgrade package...
Upgrade package is OK.
Using upgrade script extracted from local package.
Upgrade package found in local cache.
If the software is not available, manually download the software and then perform this step again.
3. After the AMP services restart, you will see the following message:
Setting up secure accounts...
Setting admin user name...
Admin Username (default 'ampadmin'):
Admin user is admpadmin
Done
Setting admin password...
Admin Password:
Verify Password:
Done
Done
Removing alias for less...
Done
AMPCLI Setup completed
Enter the new ampadmin password. If you don't enter a user name, AirWave uses the default "ampadmin".
4. After setting the password, you will see the following message:
Your system has been converted to use AMPCLI. You may now
log in as ampadmin. If you lose the password for ampadmin you
may log in as amprecovery (password recovery) on the console to reset
the ampadmin password
5. Finally, remove any OS user accounts to prevent unauthorized access.