Apple recently released the iOS firmware to version 9.2, although this minor update brings plenty of fixes and improvements behind-the-scenes, improving the experience for Apple Music, Mail, iBooks, and other Apple software as well, however not everyone is satisfied with the iOS 9.2, because the performance of this version is serious shortage in some older devices, such as iPhone 4s, iPhone 5 and iPhone 5s.
To further solve the problem, Apple officially sealed iOS 9.2.1 beta to developers, for testing improvements the company recently added. The build number for iOS 9.2.1 beta is 13D11 and it is available for all devices that are capable of running iOS 9 or above.
New version brings performance improvements to iPhone 5s, iPhone 5, and iPhone 4s.
In order to prove these improvements are really effective. iAppleBytes deliberately made three comparison test video below, the iPhone 4s clearly boots up ever so slightly quicker with the more recent software, and appears to be slightly snappier at loading built-in apps like Messages and Camera….
OS 9.2.1 also boots up faster than iOS 9.2 on iPhone 5 and iPhone 5s — as demonstrated in the videos below.
If you would like to try these improvements in iOS 9.2.1 beta and have a registered Apple Developer Account, then simply download the latest firmware form iOS Dev Center. Non-developers can download the ipsw files from IMZDL once they published the download links.