I checked the firmware on my router and it is 40.21.10.2. In the advanced section there is a firmware update button. Looks like it checks an actiontec page:
https://upgrade.actiontec.com/MI424WR-GEN3I/MI424WR-GEN3I.rmt
I checked the firmware on my router and it is 40.21.10.2. In the advanced section there is a firmware update button. Looks like it checks an actiontec page:
https://upgrade.actiontec.com/MI424WR-GEN3I/MI424WR-GEN3I.rmt