MacOS Catalina

macOS Catalina (version 10.15) released on October 7, 2019, is the sixteenth major release of OS X, renamed macOS, Apple's desktop and server operating system for Macintosh computers. It is the successor to macOS Mojave and the predecceesor to macOS Big Sur. Following the California landmark-based naming scheme introduced with OS X Mavericks, Catalina was named after Santa Catalina Island, located in Southern California.

Catalina breaks the feature/fix tick-tock cycle to become the first version of macOS to only run 64-bit software. It also does away with iTunes to provide individual applications for discrete product functionality.

Supported systems
macOS Catalina supports all computers supported by macOS Mojave, with the exception of 2010-2012 Mac Pro computers.

New products and features

 * iTunes is broken up into multiple other products. The Finder is now used for syncing iOS devices, including software and ringtone management, music is managed through Apple Music, TV and Movies are provided through Apple TV, audio podcasts are provided through Apple Podcasts.


 * Catalyst is a new API that allows software originally designed for iPad OS to also function on macOS.


 * Apple Arcade is a new subscription-based section of the App Store that provides access to the same games and game data across macOS, iOS, iPadOS and tvOS.


 * Sidecar is a new feature that lets you use a device running iPadOS 13 or later as a wireless secondary extended or mirroring monitor.  It supports the use of Apple Pencil on the iPad display during Sidecar sessions.


 * Screen Time has been ported from iOS to macOS System Preferences, to summarize how you are using your macOS software.  It also provides more control over how local users spend their time, as well as on other Apple devices via Family Sharing.  It exposes control of communication limits, combined limits, and time extensions.


 * Activation Lock has been added for all hardware using the T2 security chip. This requires secure authentication to be able to erase and re-activate your Mac.


 * Catalina also moves the System software to its own separate APFS partition that is locked for writing, replacing the System Integrity Protection mechanism used on previous versions of macOS.


 * Additionally, applications must now get permission to read/write data from the Documents and Desktop folders, iCloud Drive, and external volumes as well as to directly interact with external interface devices like keyboard input, screen capture, or video capture.


 * Find My.app has replaced Find My iPhone and Find My Friends in iCloud and on iOS devices, and is now available on macOS as well. You can now track the location of all devices registered to your Apple ID, as well as devices whose location information is shared with you.


 * Authentication handling can now be done from an Apple Watch as well as the fingerprint reader or FaceID where available.

Notable changes

 * Apple Photos has been updated with improved visualization and sorting features.


 * Notes now has a gallery view, better checklist handling, and improved collaboration tools.


 * Reminders has been replaced with a new app of the same name.  It is not backwards-compatible with older Reminders databases on-disk or in iCloud.  The new Reminders handles attachments, has new Siri Suggestions, has a Quick Edit mode, Messages integration, and new organization modes, including Tags.


 * Safari has minor improvements, including new privacy features, Messages integration and Siri Suggestions integration.