is it safe to go from v4.8 to v5.4 or do I need to apply some updates in between. This client requires as little downtime as possible, this is my first Peplink that I have managed. I wanted to be safe, not sorry.
Thanks.
Hello I would upgrade firmware in the following order:
- 5.0 firmware
- 5.3.12 firmware
- 5.4.9 firmware
An important reminder: please be sure to have your unlock key ready before upgrading to the 5.x release
Is this an official stance when going from v4 to v5?
This is the recommended path to get from 4.8.2 to the current 5.4.9 firmware. As Jarid mentioned, you will need the v5 unlock key after you upgrade to 5.0
Thanks Tim and Jarid for the information.
Can you explain the unlock key for me? I recently acquired this client in a hostile takeover, I do not have any documentation. 
Hello,
More information can be found here regarding upgrading to 5.x firmware
Basically we will need you to send in a diagnostic report to [email protected]
This can be found by logging into the webui of the balance and then going to Status>Device>Download a Diagnostic Report