It appears as though Nokia Germany are rolling out the 12070 update that addresses battery life issues and will prove to be a must-have for Lumia 800 owners. We previously looked at Singapore rolling out the Lumia 800 12070 update, and later confirmed that it tripled the battery life of our handset. As well as the juice improvements, bass has been improved and camera white balance has been tweaked.
The update, which was originally destined to be released on April 18th, will now be rolled out globally in stages / batches (starting today). April 4th, 11th, and 18th will be the three remaining steps until the update has been pushed out to every Lumia 800 (depending on networks). Note that this is not the WiFi tethering update. Be sure to keep an eye on the Nokia update section of their website to see when you'll be seeing the notification.
Source: Nokia, Nokia conversation