Apple has released the second major update to the iOS 9 operating system.

The update, called iOS 9.2, is now rolling out over the air to the public. It has been in testing since late October, when it was seeded to developers and public beta testers. Although it is the second major update to iOS 9, it's technically the fourth update to the software that debuted in September.

Apple has packaged a tonne of improvements and bug fixes in this update, including Apple Music, News, Mail, and iBook enhancements. You can now create a new playlist when adding a song to a playlist in Apple Music, and your most recently-changed playlist appears at the top when adding songs.

Also, you can download albums or playlists from your iCloud Music Library by tapping the iCloud download button and see which has been downloaded with a new indicator next to each song in My Music and Playlists. As for News, there's a new Top Stories section, with the most important news of the day.

This section is available in the US and UK. Other big improvements include a Mail Drop feature in Mail for sending large attachments, and iBooks supports 3D Touch to "peek and pop pages from the table of contents, your notes and bookmarks, or from search results inside a book".

iBooks has also been updated to support listening to an audiobook while you browse your library, read other books, or explore the iBooks Store. The update also features support for AT&T's NumberSync Wi-Fi calling feature.

Beyond all that, iOS 9.2 includes a slew of tweaks.

To download that update, simply go to Settings on your device, then General, and Software Update. The update is rolling out over the air and should arrive for you phone shortly, if it hasn't already.