Apple has released iPhone 3.1.3 OS firmware for iPhone 3G/3GS and iPod touch with some couple of bug fixes and minor updates for improved battery life. Just turn on iTunes and connect iPhone 3G/3GS to Update to firmware 3.1.3. You will notice a message confirming the new available firmware update. Click on “Download and Install” button to install the new iPhone OS 3.1.3 firmware on iPod or iPhone 3G/3GS.

Change log for iPhone 3.1.3 OS firmware
- Improved Accuracy of Reported Battery Level on iPhone 3GS
- Resolved issue where third party apps would not launch in some instances
- Fixes bug that may cause an app to crash when using Japanese kana keyboard.
View support document for more details on the security updates in iPhone OS 3.1.3
Download iPhone OS 3.1.3 (Direct Download links)
Download iPhone 2G 3.1.3 OS
Download iPhone 3G 3.1.3 OS
Download iPhone 3GS 3.1.3 OS
