https://wccftech.com/download-apple-releases-ios-15-6-and-ipados-15-6-beta-4-to-developers/

Today, Apple has seen fit to release beta 4 of iOS 15.6 and iPadOS 15.6 to developers for testing purposes. The new beta build arrives two weeks after the third developer beta was released. If you are a developer, you can download the latest iOS 15.6 and iPadOS 15.6 beta 4 on your compatible iPhone and iPad model right now. Scroll down to read more details on the subject.

As mentioned earlier, Apple has released beta 4 of iOS 15.6 and iPadOS 15.6 to developers for testing purposes. You can download the latest beta builds from the Apple Developer Center or over the air. Be sure to install the appropriate configuration profile from the Developer Center. Apple is continuing its iOS 15 updates even after the announcement of iOS 16 earlier this month. At this point, iOS 15.6 and iOS 16 are both in their beta phase.