https://wccftech.com/download-ios-15-6-and-ipados-15-6-beta-2-released/

Registered developers can download and install iOS 15.6 and iPadOS 15.6 beta on their iPhone and iPad. Apple has released other software updates too.

As we move closer to iOS 16 and other big software releases, Apple is releasing the last updates to its currently available public software. Today, the company has released the second beta of iOS 15.6 and iPadOS 15.6 to developers and the update is available over the air right away.