Those participating in Apple's beta program for iOS 13 received an unexpected update on Tuesday: the first beta of iOS 13.1. Apple typically releases several beta previews of an upcoming iOS release, followed by a finalized, or GM, build after the iPhone keynote. That build is what ultimately is released to consumers.
Going by Apple's previous release schedule, the next iOS 13 preview should have been beta 9. However, it appears this year that Apple is changing things up, and has released iOS 13.1, giving developers earlier access to the next major update to iOS and perhaps signaling the company has finished development of iOS 13 and has a build suitable for public release.
Releasing iOS 13.1 early will help developers keep up with Apple's plans and important changes to the code in OS 13, as well as potentially give us a glimpse of new features Apple is working on.
Right now, it's unclear what has changed (if anything) in iOS 13.1, but we're installing it and will report back if we find anything major.
I've reached out to Apple for comment and will update this post should I learn more.