参考 iOS & iPadOS 16.4 Beta 3 Release Notes | Apple Developer Documentation
Beta enrollment for iPhone and iPad
New Features
Beginning with iOS & iPadOS 16.4 beta, members of the Apple Developer Program will see a new option to enable developer betas directly from Software Update in Settings. This new option will be automatically enabled on devices already enrolled in the program that update to the latest beta release. Your iPhone or iPad must be signed in with the same Apple ID you used to enroll in the Apple Developer Program in order to see this option in Settings. In future iOS and iPadOS releases, this new setting will be the way to enable developer betas and configuration profiles will no longer grant access. (101692915)
从 iOS 16.4 开始，要想获得开发者测试版的系统，你只需要加入开发者计划，并在开发者计划中注册你的设备，就可以在系统更新中看到相关选项。