Apple released the macOS Catalina developer preview Beta 8, updated from the previous developer version for nearly two weeks. Earlier in the day, Apple also released the Beta 3 update for the iOS 13.1/iPadOS 13.1 developer preview.
Users can download the new macOS Catalina beta using Software Update in System Preferences. As with all new betas, there may be major bugs as it is an early release of beta software.

macOS Catalina splits the iTunes app and divides it into music, podcasts and TV apps. Apple Music and Apple Podcasts apps are now available, and Apple TV apps will be available later this year.
macOS Catalina also introduced a new Sidecar feature that converts the iPad to the second display on the Mac. Apple Pencil works with Sidecar to convert your iPad to a drawing board in applications such as Photoshop and Illustrator.
Currently, Catalina limits to developers, and Apple plans to release the official version later in the fall.
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