Recently, Apple released iOS 9.1 beta 4 for developers. This version is currently available through the Apple iOS Developer Center.
In addition, Apple has also rolled out Public Beta 4 for members participating in the Beta Software Program. To download iOS 9.1 public beta, if you haven't enrolled in the Beta Software Program, visit this website and perform the 'Enroll' operation for iPhone, iPad, or iPod touch. Then, follow the instructions provided by Apple.
If you were already using iOS 9 public beta, you can go to Settings > General > Software Update to check for updates.
https://Mytour.vn/download-tai-ios-91-beta-4-cho-lap-trinh-vien-3263n.aspx
There isn't much information available about what will change in iOS 9.1, except for new emojis in messages. As it is an experimental update, if you've agreed to install it, you must accept the fact that the operating system may be unstable and some features may not be functional.
