FRITZ!DECT 301 Service - Knowledge Base
Updating the firmware
During operation, the FRITZ!Box checks for updates for all of the registered DECT devices every 48 hours or within 30 minutes of being restarted. If the FRITZ!Box finds new firmware, it is updated automatically. This process may take several minutes. You can see which version is installed by calling up the general settings for the radiator control under "Home Network > Smart Home" in the FRITZ!Box user interface.