Apple has released a new OS X Mountain Lion 10.8.2 build to developers, little more than a week after the previous build of the operating system’s update beta.

9To5Mac reports that build 12C43 includes Facebook integration and iMessage phone number merging to make it compatible with iOS 6, which is expected to be released following Apple’s event next week.

The short gap between the last 10.8.2 build (12C35) and the latest update suggests that Apple is preparing to release the update to the public, which is likely to be around the on-sale date of the iPhone 5, possibly the 21 September if current speculation is correct.

Apple’s Mountain Lion 10.8.1 update was released to the public in August, but did little to improve battery life, a concern that was expressed by many MacBook users after installing the new OS.

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