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
(kernel extensions). 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.
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.
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.
