As of June 01, 2020, all units shipped by ZPE should have the following firmware versions installed in each modem:

SWI9X50C_01.07.02.00_ATT_002.008_004

SWI9X50C_01.08.04.00_GENERIC_002.012_001

SWI9X50C_01.08.04.00_VERIZON_002.015_002

Upgrading Firmwares 

Depending on the date the units was purchased, the pre-installed firmware versions will vary. In case your modem doesn't have the versions above, then the upgrade process is fairly simple.