https://techcrunch.com/2019/08/27/apple-releases-first-beta-of-ios-13-1-indicating-ios-13-is-nearly-done/

Surprise, Apple didn’t release yet another beta version of iOS 13. The company released the first developer beta of iOS and iPadOS 13.1 instead.

This is a curious move as Apple doesn’t usually share beta versions of .1 updates before the release of major updates. What’s even more surprising is that Apple released new beta versions for watchOS 6.0 and tvOS 13.0 today.