Apple Released iPhone and iPod Touch OS 3.1.3, JAILBREAKERS and UNLOCKERS DO NOT UPDATE
WARNING! On February 2nd 2010 Apple released the 3.1.3 version (7E18) of the iPhone and iTouch OS. Jailbreakers DO NOT UPDATE!!!
If you care about your jailbreak and unlock, don’t update your device - 3G and 3G(S) owners should pay particular attention to this warning
Apple just released OS 3.1.3, which you can download right now through iTunes. The new firmware update (3.1.3) was pushed on Tuesday February 2nd, 2010 for all iPhone and iPod touch users which brought some important security and bug fixes.
Features wise, there was nothing new to be seen in the firmware. The only new features mentioned are improved reporting of battery level on the iPhone 3G S, fixes for problems with the Japanese Kana keyboard, and some issues where third-party apps would fail to launch.
Since this firmware updates the baseband to 05.12.01 on iPhone 3GS and 3G, so do not update your device (iPhone or iTouch) to this firmware if you want to preserve your unlock on iPhone 3G and iPhone 3GS.
Upgrading to new iPhone firmware OS version 3.1.3 would break existing jailbreak and unlock. iPhone and iPod touch owners who jailbreak and unlock their device should not upgrade to iPhone OS 3.1.3.
To upgrade iPhone and iPod Touch just connect the mobile device to PC and start iTunes. You would get the update message message automatically. Download the the individual standalone iPhone Firmware Update file (IPSW) for manual offline updating from our Firmware Downloads Page