On the test, I will update the firmware PowerBeam 5AC 500 (with version 7.1.4) and PowerBeam 5AC 620 (with version 7.0.3).
I will describe the update procedure:
1) Download the new firmware from the official site:
https://www.ubnt.com/download/airmax-ac/powerbeam-ac
2) Open the device web-interface by typing its IP-address in the browser (default 192.168.1.20, default login “ubnt”, password also “ubnt”).
3) In the web-based interface on the left, click “System”, opposite “Upload Firmware:” click “BROWSE” and select the previously downloaded firmware, a window will appear in which click “Upload”, in the next window click “Upgrade” and wait for the upgrade to complete.
Power at the time of the update can not be turned off, otherwise you may need to restore the firmware via TFTP.
How to recover I wrote in this article:
Ubiquiti (UBNT) device recovery
This completes the update procedure.
By the way, with firmware 7.0.3 to 7.2 it was not immediately possible to update, I had to update first on XC.v7.1-rc (it was also available for download on the official website using the link above), after installing XC.v7.1-rc, version 7.2 is installed.