Update Android version on Panasonic KX-UT670 I have to build an application that uses Google Contacts API.

This application must be used on a Panasonic KX-UT670 that has Android 2.2 as SO, but i need to upgrade it at least to 2.3, as documentation says here

I searched around internet but i didn't find how to upgrade the Android version on it.
That device is not a Smartphone or Tablet, it is known as Smart Desk Phone, i tried to go to the device settings, but there are nothing to upgrade the SO.

Does anybody knows how can i update Android version on that device?
Actually, reading the developer manual, it seems you can't


  Applications developed by using KX-UT670 APIs are exclusively for use with the KX-UT670. 


That, IMHO, implies they have it's own API, thus you have to develop in this API to make an app AND you cannot update, or upgrade Android version in the device. 

Yes, it is Android 2.2 version, but not an open one... :(