iOS 6.1.3:
This update contains improvements and other bug fixes including:
● Fixes a bug that could allow someone to bypass the passcode and access the Phone app
● Improvements to Maps in Japan
iOS 6.1.3, which arrives as Build 10B329, also reportedly addresses at least one of the security holes used by the evasi0n jailbreak tool, so users interested in jailbreaking their devices will undoubtedly want to hold off on upgrading until more information surfaces.