The Mountain Lion OS X 10.8.3 beta was seeded on Tuesday, with build number 12D43. It has no known issues or new features, but Apple has asked developers to focus their testing on AirPlay, AirPort, Game Center, Graphics Drivers and Safari, MacRumors reports.
The first beta of Mountain Lion OS X 10.8.3 was seeded in November, followed by a second beta ten days later on 6 December.
Earlier this week, Apple also released the iOS 6.1 beta 4 for developers as an over-the-air update, labelled as build 10B5126b. The new version contains bug fixes and improvements, reports Apple Insider. It arrives two weeks after the third beta was seeded to developers.
Alongside iOS 6.1 beta 4, Apple seeded Xcode 4.6 Preview and Apple TV software update beta 3.
These beta updates have been made available to developers as the public have been given an iOS 6.0.2 update for iPhone and iPad mini that is said to fix a WiFi bug.
Also this week, Apple posted updates to the Wi-Fi and EFI firmware for almost all of the Macs it released in 2012.