1) From Idle screen press 
to enter main menu.
2) Press 
and to select Settings.
3) Press and to select Advanced.
4) Press and to select Firmware update.
5) Press and or just to select the required option (Last Firmware, Current Firmware, All Firmware vers.).
6) Under Lastest Firmware, pressto install. Please be aware that the download can take some time. The handset will promt you when the firmware update is finished.
7) Under Current Firmware, you find the specifications of the firmware version presently used by the base station and the handset.
8) Under All Firmware vers., you can see prior updates. Press and or just press to select your preferred version.
9) Press again to install the selected version. You will then be asked if you are sure you want to update. Press to accept, 
to decline.
Note:
