Apple has just made available to developers the iOS 13.1 beta 4 (build 17A5844a), the iPadOS 13.1 beta 4 (idem) and the tvOS 13 beta 11 (17J5584a).
The three systems will be released to the general public on September 30, so Apple is certainly working hard to make them as round as possible. IOS 13.0, which arrives for everyone tomorrow with watchOS 6, does not bring all the news promised in WWDC19 and still contains some annoying minor bugs.
So far, there is no Apple Developer portal on iOS 13.1 beta 4 builds for the iPhones 11, 11 Pro, and 11 Pro Max critical for those who put their hands on them this Friday to be able to restore backups of devices running those latest betas. It may be that Apple decided to upload them to the portal itself Friday, however (hopefully).
As always, if something new comes out of relevance in these versions today, we'll let you all know here on the site! 😉