OS X Mountain Lion

OS X Mountain Lion, or OS X 10.8, is the ninth major release of the OS X operating system released on 25 July 2012. It was announced on 16 February 2012 on Apple's website. It introduced various revamps to the Lion user interface and fixed many of the paradigms that were found to be controversial in Lion.

Like in iOS 11, this version of OS X is the first to drop support for 32-bit kernels and corresponding 32-bit EFI BootROM Macs. The decision to drop 32-bit architectures was made relatively late in the development process, as Beta 1 (12A128p) shipped with a 32-bit kernel. This version drops support for NVIDIA GeForce 6000/7000 Series, ATi Radeon X800/X1000 Series and Intel GMA 900/950/3150/X3100 (Mobile 965 Express Chipset Family) graphics cards.

It is the first version to be released under the OS X name. It is also the first version to be released under the new annual release schedule for the operating system in which newer versions of OS X will be released annually in order to be consistent with the release schedule for iOS.

It is the last version of OS X to be released as a paid upgrade as subsequent releases would be released as free upgrades starting with OS X Mavericks.

New features and changes

 * AirPlay Mirroring has been added, which allows wireless mirroring of the Mac's screen to an Apple TV.
 * Notification Center has been added, which is a system-wide notification feature that can be accessed by clicking in the right-corner of the menu bar.
 * Launchpad now has the ability to search installed applications.
 * Game Center, Notes, and Reminders from iOS have been added.
 * The Messages app was added to replace iChat. It supports iMessage and has native video conversation support through FaceTime.
 * The Address Book and iCal apps have been renamed to Contacts and Calendar respectively.
 * Social media integration for Twitter and Facebook has been added.
 * The Mac App Store can now install app updates automatically.
 * Software Update and its functionalities were moved to the Mac App Store.
 * Dictation functionality has been added.
 * System-wide integration of AirPlay audio transmission was added.
 * A new security feature called Gatekeeper was added. It enforces code signing and checks downloaded applications before they can run, reducing the likelihood of executing malware.
 * Dashboard has been updated slightly to resemble the UI of Launchpad when editing Widgets.
 * The design of the Dock has been updated slightly, and the separator no longer resembles as a crosswalk.
 * The Preview app has an updated UI.