Hubitat does not currently support OTA firmware updates. Staff have indicated in the past that they are open to this possibility but have no timeline (see here, and probably more recent posts I can't find). However, even if Hubitat supported this, there's no guarantee manufacturers would provide the firmware.
The good news is that there's usually no reason to do a firmware update if your device is working fine (and it doesn't fix some critical vulnerability, etc.). This is almost always the case--I probably have lots of devices that could be updated, but I see no reason to on any of them. In fact, I wish I could roll my Zen Thermostat back to an older version (ST updated it and fan mode control hasn't worked reliably remotely since).
