Apple has released iOS 13.4.5 beta 1 to developers for testing with build number is 17F5034c. with lots of bug fixes and improvements. Also the new added feature to share songs from Apple Music directly to Instagram Stories.
Other than that, iOS 13 introduces new features like Dark Mode, new browsing and editing tools for Photos, Sign in With Apple, enhancements to Maps, updates to Reminders, Notes, Messages, Siri, CarPlay, Files, and much more.
Downloading and Installing iOS 13.4.5 & iPadOS 13.4.5 Developer beta 1
The registered developers can download and try the iOS 13.4.5 & iPasOS 13.4.5 beta 1 from Apple Developer Center or via OTA(over-the-air) mechanism with the proper configuration profile that can be installed from the Developer Center.