Before upgrading, please ensure that your version is not one of the aforementioned versions (8.1.3, 8.2.1, 8.2.2 or 8.2.3). If it is, please apply this patch to resolve the hanging issue during the upgrade process. Once the patch is applied, you should be able to upgrade without any issues.
To download the patch, you will need your 16-digit license key which will function as both the username and the password. Download the nsr823-upgrade-update.zip file and copy it to the /home directory on the appliance.
As root, run the following commands:
Perform the upgrade to 8.2.5 as normal.