updated 06:31 pm EDT, Mon July 9, 2012
Lion 10.7.5 update also available for testing
The finishing touches are being applied to the next major release of OS X, dubbed Mountain Lion or 10.8. Developers have alerted MacNN to a Golden Master (GM) seed being pushed out through the OS X Dev Center. The GM seed is for both the client version as well as Server, which features a significant re-arranging of its main features. The company also has a first seed of Lion 10.7.5 and a GM of Xcode 4.4 available.
A Golden Master is usually the last stage of OS X development before what used to be termed "Release to Manufacture" (RTM) back when OS X came out on discs that had to be printed. It is a near-final version of Mountain Lion that is not expected to have any major flaws, and gives developers one last chance to see if issues they've encountered now work correctly (or find any last-minute bugs). Interestingly, the build number on the GM release is not in sync with the releases up to this point. The last version of Mountain Lion for had a build number of 12A526, while the new GM built is labeled 12A269. The server version is labeled 12S302.
Mountain Lion is expected to offer nearly 200 new and improved features, but one of the most significant to veteran users is also one of the least-mentioned by Apple: starting with 10.8, Software Update will be handled by the Mac App Store, making it the official channel for all system and Apple app updates and unifying the two update systems. Other major features include the integration of the iOS Notification Center, Messages, Reminders as its own app, Notes and Game Center, but there are also several new features that are not drawn from iOS such as "Power Nap" (which allows Macs to do system updates and sync tasks even while asleep), the ability to go full-screen on any monitor, an offline Reading List for Safari, the new Gatekeeper anti-malware protection system and significant additions to Mail and Preview along with many other changes.
Apple also unveiled a new developer seed of Lion 10.7.5, which is noted as build 11G22. The update is likely to have the usual clutch of bug fixes, but is also expected to add or help maintain compatibility between services in Lion (such as Address Book) and Mountain Lion (where the same app is now called Contacts and has some different features). Also released was the GM of Xcode 4.4, the developer tool that allows programmers to create applications for Mountain Lion. The release supersedes Xcode 4.4 DP6. The delta version of the 10.7.5 update is 1.03GB in size, while the combo version is 1.91GB.