Upgrade APC Firmware - AP7921 Switched Rack PDU

Evening Everyone,

I have acquired an APC Switched Rack PDU AP7921 . I am using it in my home lab setup. I have noticed that it is running an older version of the firmware. 

Can someone run me through the upgrade process? When i looked on APC's website i can only find the firmware for  AP7921B. Not sure if this would work with my device or not. 

Thanks in advance for the assistance.