Weighing in at 44MB, users are reporting improvements to the proximity sensor, fixes to the camera shutter sound, and improved voice mail.
Here is the official changelog, as listed on the Sprint Community Forum:
- Proximity sensor improvements while on a call or listening to voicemail
- Ability to output audio/video to HDTV (and other external displays via MHL cable
- WiFi Connection improvements
- Bluetooth compatibility improvements
- Android process/application shutdown resolved
Source: Android Central