This release includes new features, improvements and bug fixes, including:
• Live Photos now intelligently senses when you raise or lower your iPhone, so that Live Photos will automatically not record these movements
• Over 150 new emoji characters with full support for Unicode 7.0 and 8.0 emojis
• Improved stability including CarPlay, Music, Photos, Safari and Search
• Improved performance while in Multitasking UI
• Fixes an issue that could cause Calendar to become unresponsive in Month view
• Fixes an issue that prevented Game Center from launching for some users
• Resolves an issue that zoomed the content of some apps
• Resolves an issue that could cause an incorrect unread mail count for POP mail accounts
• Fixes an issue that prevented users from removing recent contacts from new mail or messages
• Fixes an issue that caused some messages to not appear in Mail search results
• Resolves an issue that left a grey bar in the body of an Audio Message
• Fixes an issue that caused activation errors on some carriers
• Fixes an issue that prevented some apps from updating from the App Store
* brings Apple News to the UK and Australia for the first time.
iTunes 12.3.1 comes just over a month after the release of iTunes 12.3, which brought support for iOS 9 and OS X El Capitan.
iTunes 12.3.1 doesn’t introduce any new features and simply “improves overall stability and performance” of your Mac, according to release notes accompanying the download.
 About the security content of iOS 9.1 HT205370 (2015-Oct-21) [Apple]
 About the security content of iTunes 12.3.1 HT205372 (2015-Oct-21) [Apple]
 Apple Releases Updates for iOS, WatchOS, OS X, Safari and iTunes. (2015-Oct-21) [SANS]