Yesterday Apple released the Golden Master version of iOS 4.2 to developers for both iPad and iPhone and iPod touch devices. The GM build is typically the final shipping build that will eventually reach customers. That means that the company is really close to public release of the new operating system.

With this update Apple:

• brought AirPlay and returned it as a feature to YouTube;

• finally brought multitasking features and iOS Folders to the iPad, support for multiple email aliases, a unified inbox, and messages organized by threads in Mail, and the ability to open attachments in third party apps;

• replaced the iPad’s button for  the screen orientation locking with the mute button;
• brought Game Center to the iPad, allowing players to invite friends or find new opponents online to play against, as well as track their own achievements and high scores;
• brought support for more than 30 new languages in keyboards and dictionaries.