In the 8.2.3 release notes, we've included a new section with the instructions for upgrade.
For any AirWave release, you have 2 methods:
1) automatic
2) manual
For automatic upgrade, you need to make sure you have a valid account on support.arubanetworks.com as the download uses your support site creds to download the upgrade package:
# start_amp_upgrade -v <desired.upgrade.version>
for example:
# start_amp_upgrade -v 8.2.3
---AMP will check if upgrade package exists
---when it doesn't find upgrade package, it will prompt for support site credentials
---then it will download and proceed with upgrade
For manual upgrade, you'll want to download the upgrade package from the support site. Upload the upgrade tarball into the /root directory. Then run the same upgrade cmd:
# start_amp_upgrade -v <desired.upgrade.version>
for example:
# start_amp_upgrade -v 8.2.3
---AMP will check if upgrade package exists
---when it find's that the package is there
---it will proceed with the upgrade