There are two flash banks utilized for firmware. Each time you upgrade the firmware the device will utilize the alternate flash bank, the bank it is not currently running on. The device has a maximum of two firmware versions available to boot from. The WAN license key will apply to all firmware versions. We do recommend updating the device to the most recent firmware available to ensure you have all of the available improvements and feature additions incorporated with the newest firmware release.
You may select the firmware version, or flash bank, to boot from manually by accessing the web admin, select “System” on the top > “Reboot” on the left side and then select the flash bank and associated firmware you would like to run. Note that after entering the license key it will apply to the current firmware and future upgrades, you may need to enter it again if you select the firmware that was running prior to entering the license key.