Apple released iOS 13.2 back on October 28, and as is traditional, Apple has now stopped signing iOS 13.1.3 and iOS 13.1.2, making downgrading to those versions of iOS no longer possible.
iOS 13.1.3 was a minor update released in mid-October, and included bug fixes for Health, iCloud, Mail, Phone, and more. iOS 13.1.2 was another minor bug fix update.
Apple is known to stop signing older versions of operating systems after it releases a public update, as part of an effort to encourage users to keep their devices’ operating systems up to date.
iOS 13.2 is the current public version of iOS, and includes new support for AirPods pro, new emojis, and Deep Fusion for the iPhone 11, iPhone 11 Pro, and iPhone 11 Pro Max.
iOS 13.3 is currently in beta, and is being tested by developers and public beta testers. The upcoming update introduces Communication Limits for Screen Time.