My least favorite engineering problem is the "dusty router" concern.

At some point, you may want to version your apis in a breaking way. You'll spend weeks sketching out a migration plan for all active routers in the field, sell it internally , get a thumbs up, then try to prep customer support. Customer support might tell you that you still need to support some devices which were unplugged on a firmware released 6 months ago. Oops.

When building deployed firmware, you always need to include a reliable fallback that allows you to bump the firmware on that device, even when it can't talk to anything else wirelessly.

sounds like you should've talked to customer service first :)