As per usual, Apple has now stopped signing code for the most recent previous release of iOS 9, version 9.0.2, as a security measure. The move also effectively blocks users from downgrading to the previous version, which may be needed for jailbreaking. In addition to bug fixes and security updates, iOS 9.1 also introduced several new features, such as support for Unicode 8 and subsequent new emojis, along with the Live Photos feature for owners of the iPhone 6s or iPhone 6s Plus.
