Some regions have already received the 12072 update while others haven't. If you own the Nokia Lumia 800, you can either wait for the update from Nokia to reach your area or take the risk of downloading it before the release. If you attempt the latter, you will be doing it at your own risk. Check out the instructions below from Mobiletechworld.
- Download the update from the first link above then download the WPupdate tools from here.
- Unzip the Tools in a folder then copy the firmware to the same folder as the tools.
- Plug in your device, wait until the Zune client starts and then close it.
- Run the the Updater and press S or B (depending on the size of your balls..)
- your phone will then reboot in download mode and update (don’t unplug it or do stupid things with your PC during the whole process..)
source: MobileTechWorld via WMPoweruser