# MacOS Catalina

macOS Catalina (version 10.15) is the sixteenth major release of macOS, Apple Inc.'s desktop operating system for Macintosh computers. It is the successor to macOS Mojave and was announced at WWDC 2019 on June 3, 2019 and released to the public on October 7, 2019. Catalina is the first version of macOS to support only 64-bit applications and the first to include Activation Lock. It is also the last version of macOS to have the major version number of 10; its successor, Big Sur, released on November 12, 2020, is version 11. In order to increase web compatibility, Safari, Chromium and Firefox have frozen the OS in the user agent running in subsequent releases of macOS at 10.15.7 Catalina.
The operating system is named after Santa Catalina Island, which is located off the coast of southern California.
macOS Catalina is the final version of macOS that supports the Unibody MacBook Pro, as its successor, macOS Big Sur, drops support for its mid-2012 and final model.

## System requirements

All standard configuration Macs that supported macOS Mojave support macOS Catalina. 2010 to 2012 Mac Pros, which could run Mojave only with a GPU upgrade, are no longer supported. Catalina requires 4 GB of memory, an increase over the 2 GB required by Lion through Mojave.
* iMac (Late 2012 or later)
* iMac Pro (2017)
* MacBook (Early 2015 or later)
* MacBook Air (Mid 2012 or later)
* MacBook Pro (Mid 2012 or later)
* Mac Mini (Late 2012 or later)
* Mac Pro (Late 2013 or later)
It is unofficially possible to install macOS Catalina on many older Macintosh computers that are not officially supported by Apple. This requires using a patch to modify the install image. (dosdude1)'s Catalina Patcher is an example of those tools, which can be used to Install Catalina on machines between 2008 and 2011.

## Changes
### System
#### Catalyst

Catalyst is a new software-development tool that allows developers to write apps that can run on macOS, iOS and iPadOS. Apple demonstrated several ported apps, including Jira and Twitter (after the latter discontinued its macOS app in February 2018).

#### System extensions

An upgrade from Kexts. System extensions avoid the problems of Kexts. There are 3 kinds of System extensions: Network Extensions, Endpoint Security Extensions, and Driver Extensions. System extensions run in userspace, outside of the kernel. Catalina will be the last version of macOS to support legacy system extensions.

#### DriverKit

A replacement for IOKit device drivers, driver extensions are built using DriverKit. DriverKit is a new SDK with all-new frameworks based on IOKit, but updated and modernized. It is designed for building device drivers in userspace, outside of the kernel.

#### Gatekeeper

Mac apps, installer packages, and kernel extensions that are signed with a Developer ID must be notarized by Apple to run on macOS Catalina.

#### Activation Lock

Activation Lock helps prevent the unauthorized use and drive erasure of devices with an Apple T2 security chip (2018, 2019, and 2020 MacBook Pro; 2020 5K iMac; 2018 MacBook Air, iMac Pro; 2018 Mac Mini; 2019 Mac Pro).

#### Dedicated system volume

The system runs on its own read-only volume, separate from all other data on the Mac.

#### Voice control

Users can give detailed voice commands to applications. On-device machine processing is used to offer better navigation.

#### Sidecar

Sidecar allows a Mac to use an iPad (running iPadOS) as a wireless external display. With Apple Pencil, the device can also be used as a graphics tablet for software running on the computer. Sidecar requires a Mac with Intel Skylake CPUs and newer (such as the fourth-generation MacBook Pro), and an iPad that supports Apple Pencil.

#### Support for wireless game controllers

The Game Controller framework adds support for two major console game controllers: the PlayStation 4's DualShock 4 and the Xbox One controller.

#### Time Machine

A number of under-the-hood changes were made to Time Machine, the backup software. For example, the manner in which backup data is stored on network-attached devices was changed, and this change is not backwards-compatible with earlier versions of macOS. Apple declined to document these changes, but some of them have been noted.

### Applications
#### iTunes

iTunes is replaced by separate Music, Podcasts, TV and Books apps, in line with iOS. iOS device management is now conducted via Finder. The TV app on Mac supports Dolby Atmos, Dolby Vision, and HDR10 on MacBooks released in 2018 or later, while 4K HDR playback is supported on Macs released in 2018 or later when connected to a compatible display.

#### Find My

Find My Mac and Find My Friends are merged into an application called Find My.

#### Notes

The Notes application was enhanced to allow better management of checklists and the ability to share folders with other users. The application version was incremented from 4.6 (in macOS 10.14 Mojave) to 4.7.

#### Reminders

Among other visual and functional overhauls, attachments can be added to reminders and Siri can intelligently estimate when to remind the user about an event.

#### Voice Memos

The Voice Memos application, first ported from iOS to the Mac in macOS 10.14 Mojave as version 2.0, was incremented to version 2.1.

#### Removed or changed components

macOS Catalina exclusively supports 64-bit applications. 32-bit applications no longer run (including all software that utilizes the Carbon API as well as QuickTime 7 applications, image, audio and video codecs). Apple has also removed all 32-bit-only apps from the Mac App Store.
Z shell (executable "zsh") is the default login shell and interactive shell in macOS Catalina, replacing Bash, the default shell since Mac OS X Panther in 2003. Bash continues to be available in macOS Catalina, along with other shells such as csh/tcsh and ksh.
Dashboard has been removed in macOS Catalina.
The ability to add Backgrounds in Photo Booth was removed in macOS Catalina.
The command-line interface GNU Emacs application was removed in macOS Catalina.
Built-in support for Perl, Python 2.7 and Ruby are included in macOS for compatibility with legacy software. Future versions of macOS will not include scripting language runtimes by default, possibly requiring users to install additional packages.
Legacy AirDrop for connecting with Macs running Mac OS X Lion, Mountain Lion and Mavericks, or 2011 and older Macs has been removed.
Support for legacy Safari extensions such as uBlock Origin, and WebSQL has been removed in Safari 13.

## Security

Ars Technica reported that macOS Catalina contained a critical privilege escalation vulnerability, which resulted in a backdoor being installed if users visited a Hong Kong pro-democracy website. The vulnerability was reported to Apple in August 2021 and patched in a Catalina update in September, but it had already been patched by Apple in macOS Big Sur 11.2, released 234 days earlier on February 1. Security experts have criticized Apple for not patching critical known vulnerabilities in older versions and for not being transparent about older versions only receiving some, but not all, security patches. The latest major release of Apple's operating systems (macOS, iOS, and others) receive all security updates.

## Reception

Catalina received favorable reviews on release for some of its features. However, some critics found the OS version distinctly less reliable than earlier versions. The broad addition of user-facing security measures (somewhat analogous to the addition of User Account Control dialog boxes with Windows Vista a decade earlier) was criticized as intrusive and annoying.

## Release history

| Version | Build | Date | Darwin version | Release Notes | Standalone download |
| 10.15 | 19A583 | October 7, 2019 | 19.0.0 | Original Software Update release Security content | |
| 10.15 | 19A602 | October 15, 2019 | 19.0.0 | Supplemental update | |
| 10.15 | 19A603 | October 21, 2019 | 19.0.0 | Revised Supplemental update | |
| 10.15.1 | 19B88 | October 29, 2019 | 19.0.0 xnu-6153.41.3~29 | About the macOS Catalina 10.15.1 Update Security content | macOS 10.15.1 Update |
| 10.15.2 | 19C57 | December 10, 2019 | 19.2.0 xnu-6153.61.1~20 | About the macOS Catalina 10.15.2 Update Security content | macOS 10.15.2 Update macOS 10.15.2 Combo Update |
| 10.15.2 | 19C58 | December 10, 2019 | 19.2.0 xnu-6153.61.1~20 | About the macOS Catalina 10.15.2 Update Security content | macOS 10.15.2 Update macOS 10.15.2 Combo Update |
| 10.15.3 | 19D76 | January 28, 2020 | 19.3.0 xnu-6153.81.5~1 | About the macOS Catalina 10.15.3 Update Security content | macOS 10.15.3 Update macOS 10.15.3 Combo Update |
| 10.15.4 | 19E266 | March 24, 2020 | 19.4.0 xnu-6153.101.6~15 | About the macOS Catalina 10.15.4 Update Security content | macOS 10.15.4 Update macOS 10.15.4 Combo Update |
| 10.15.4 | 19E287 | April 8, 2020 | 19.4.0 xnu-6153.101.6~15 | Supplemental update | macOS 10.15.4 Supplemental Update |
| 10.15.5 | 19F96 | May 26, 2020 | 19.5.0 xnu-6153.121.1~7 | About the macOS Catalina 10.15.5 Update Security content | macOS 10.15.5 Update macOS 10.15.5 Combo Update |
| 10.15.5 | 19F101 | June 1, 2020 | 19.5.0 xnu-6153.121.2~2 | Supplemental update Security content | macOS 10.15.5 Supplemental Update |
| 10.15.6 | 19G73 | July 15, 2020 | 19.6.0 xnu-6153.141.1~9 Jul 5 00:43:10 PDT 2020 | About the macOS Catalina 10.15.6 Update Security content | macOS 10.15.6 Update macOS 10.15.6 Combo Update |
| 10.15.6 | 19G2021 | August 12, 2020 | 19.6.0 xnu-6153.141.1~1 Jun 18 20:49:00 PDT 2020 | Supplemental update | macOS 10.15.6 Supplemental Update |
| 10.15.7 | 19H2 | September 24, 2020 | 19.6.0 xnu-6153.141.2~1 Mon Aug 31 22:12:52 PDT 2020 | About the macOS Catalina 10.15.7 Update Security content | macOS 10.15.7 Update macOS 10.15.7 Combo Update |
| 10.15.7 | 19H4 | October 27, 2020 | 19.6.0 xnu-6153.141.2~1 Mon Aug 31 22:12:52 PDT 2020 | About the macOS Catalina 10.15.7 Update Security content | macOS 10.15.7 Update macOS 10.15.7 Combo Update |
| 10.15.7 | 19H15 | November 5, 2020 | 19.6.0 xnu-6153.141.2.2~1 Thu Oct 29 22:56:45 PDT 2020 | Supplemental update Security content | macOS 10.15.7 Supplemental Update macOS 10.15.7 Supplemental Update (Combo) |
| 10.15.7 | 19H114 | December 14, 2020 | 19.6.0 xnu-6153.141.10~1 Tue Nov 10 00:10:30 PST 2020 | About the security content of Security Update 2020-001 | Security Update 2020-001 (Catalina) |
| 10.15.7 | 19H512 | February 1, 2021 | 19.6.0 xnu-6153.141.16~1 Tue Jan 12 22:13:05 PST 2021 | About the security content of Security Update 2021-001 | Security Update 2021-001 (Catalina) |
| 10.15.7 | 19H524 | February 9, 2021 | 19.6.0 xnu-6153.141.16~1 Tue Jan 12 22:13:05 PST 2021 | Supplemental Update Security content | macOS Catalina 10.15.7 Supplemental Update 2 |
| 10.15.7 | 19H1030 | April 26, 2021 | 19.6.0 xnu-6153.141.28.1~1 Mon Apr 12 20:57:45 PDT 2021 | About the security content of Security Update 2021-002 | Security Update 2021-002 (Catalina) |
| 10.15.7 | 19H1217 | May 24, 2021 | 19.6.0 xnu-6153.141.33~1 Thu May 6 00:48:39 PDT 2021 | About the security content of Security Update 2021-003 | Security Update 2021-003 (Catalina) |
| 10.15.7 | 19H1323 | July 21, 2021 | 19.6.0 xnu-6153.141.35~1 Thu Jun 22 19:49:55 PDT 2021 | About the security content of Security Update 2021-004 | Security Update 2021-004 (Catalina) |
| 10.15.7 | 19H1417 | September 13, 2021 | 19.6.0 xnu-6153.141.40~1 Tue Aug 24 20:28:00 PDT 2021 | About the security content of Security Update 2021-005 | Security Update 2021-005 (Catalina) |
| 10.15.7 | 19H1419 | September 23, 2021 | 19.6.0 xnu-6153.141.40.1~1 Thu Sep 16 20:58:47 PDT 2021 | About the security content of Security Update 2021-006 | Security Update 2021-006 (Catalina) |
| 10.15.7 | 19H1519 | October 25, 2021 | 19.6.0 xnu-6153.141.43~1 Tue Oct 12 18:34:05 PDT 2021 | About the security content of Security Update 2021-007 | Security Update 2021-007 (Catalina) |
| 10.15.7 | 19H1615 | December 13, 2021 | 19.6.0 xnu-6153.141.50~1 Sun Nov 14 19:58:51 PST 2021 | About the security content of Security Update 2021-008 | Security Update 2021-008 (Catalina) |
| 10.15.7 | 19H1713 | January 26, 2022 | 19.6.0 xnu-6153.141.51~3 Thu Jan 13 01:26:33 PST 2022 | About the security content of Security Update 2022-001 | Security Update 2022-001 (Catalina) |
| 10.15.7 | 19H1715 | February 14, 2022 | 19.6.0 xnu-6153.141.51~3 Thu Jan 13 01:26:33 PST 2022 | Security Update 2022-002 | Security Update 2022-002 (Catalina) |
| 10.15.7 | 19H1824 | March 14, 2022 | 19.6.0 xnu-6153.141.59~1 Tue Feb 15 21:39:11 PST 2022 | About the security content of Security Update 2022-003 | Security Update 2022-003 (Catalina) |
| 10.15.7 | 19H1922 | May 16, 2022 | 19.6.0 xnu-6153.141.62~1 Mon Apr 18 21:50:40 PDT 2022 | About the security content of Security Update 2022-004 | Security Update 2022-004 (Catalina) |
| 10.15.7 | 19H2026 | July 20, 2022 | 19.6.0 xnu-6153.141.66~1 Tue Jun 21 21:18:39 PDT 2022 | About the security content of Security Update 2022-005 | Security Update 2022-005 (Catalina) |