Left is before the update. Right is after the update.

The T-Mobile version of the new Moto X just received its first big update last night. This update, version 139.12.57, brings a host of new fixes, features and functionality. The most significant of these is a large improvement to its picture taking capabilities. The primary difference is that pictures in backlit and low-light settings are much improved.

*Just FYI... T-Mobile currently doesn't offer the Moto X on one of their payout pricing plans. The only way to use the phone on their network is to purchase it outright for $600.

Here's the full changelog:

  • Camera – Improved Photo Quality: Improved capture of natural light (auto-white balance) and color accuracy for more precise exposure in outdoor and backlit scenes
  • Camera – Improved Focus: Faster touch to focus time and reduced unnecessary refocusing in low light conditions and scenes with continuous motion
  • Camera – Faster Switching: Shortened the time it takes to switch between rear and front-facing cameras, as well as transition between the viewfinder and the Gallery app
  • Enhanced Touchless Control: Increased accuracy and responsiveness when using Touchless Control, and added easier training of the “OK Google Now” trigger
  • Improved Motorola Migrate Experience: Improved transfer of content from an old Android phone to a new Motorola phone
  • Google Drive – 50GB Promotion: Added a promotion expiration date - customers have 30 days from phone activation or installation of this update to redeem the 50GB offer
  • Calling – Improved Voice Quality: Fixed an issue that could sometimes result in choppy audio being heard by the person you’re talking with on your Moto X
  • Moto Care – Lost Device Finder: Fixed an issue that could sometimes prevent a lost phone from reporting its location to the Moto Care Lost Device Finder service
  • Motorola Assist – Driving Detection: Fixed an issue that could sometimes cause the phone to read out text messages and announce calls when not in Drive mode
Source: Motorola