https://wccftech.com/download-beta-8-of-ios-15-and-ipados-15-released/

You can now go ahead and download beta 8 of iOS 15 and iPadOS 15 for iPhone and iPad over the air if you are a developer.

We are spectacularly close to the launch of the iPhone 13, and it will be accompanied with new software right after. Today, the beta version of that software was seeded to developers and you go right ahead and install it if you have a previous version installed.