Update for Windows Phone OS 7.10.8107 is now available for the Nokia Lumia 800 via Zune.
According to the Windows Phone Update History page, here is what is updated in this release -
On-screen keyboard. Fixes an issue to prevent the keyboard from disappearing during typing.
Email. Fixes a Google mail syncing issue.
Location. Fixes a location access issue. With this fix, the Me feature in the People Hub sends anonymous information about nearby Wi-Fi access points and cell towers to Microsoft only if you agree to allow the Check In function to access and use location information.
Security. Revokes digital certificates from DigiCert Sdn Bhd to address an encryption issue.
Email threads. Fixes an email issue related to Microsoft Exchange Server 2003. With this fix, when you reply to or forward a message, the original message is now included in your response.
Voicemail. Fixes a voicemail notification display issue that occurs on some European and Asian networks under certain conditions.
Additionally, this update was supposed to bring the much needed Charging & Power Improvements to the Nokia Lumia 800. We’ll try can confirm from Nokia whether this is the update which brings those improvements as well.
Nevertheless, update your Lumia’s via Zune right away! Here’s a helpful video incase you’re doing this for the first time: