During operation, the FRITZ!Box checks for updates for all of the registered DECT devices every 48 hours and within 30 minutes of being restarted. If the FRITZ!Box finds new firmware, it is updated automatically. This process may take several minutes. The firmware version it finds depends on the version of FRITZ!OS installed on the FRITZ!Box. You can see which version is installed by calling up the general settings for the smart home device under "Smart Home" in the FRITZ!Box user interface.