Starting in firmware version 23.12.1.56, the watchdog system inside the Digi router will automatically re-power the cellular modem inside the Digi router if the modem is not initialized for more than one hour, and reboot the entire Digi router if the modem is un-initialized for more than 2 hours.  Please read the release notes for information on disabling this option.

Before upgrading the EX12’s cellular modem firmware to 25.21.663 or newer, the EX12 must be running firmware version 23.3.31.x or newer. The 25.21.663 and newer modem firmware is incompatible with previous EX12 firmware versions when using AT&T SIMs and will cause the EX12 to lose cellular connectivity on AT&T networks.