Update your apps to use new features, and test your apps against API changes.
The macOS 10.15 SDK provides support for developing apps for Macs running macOS Catalina 10.15. The SDK comes bundled with Xcode 11 available from the Mac App Store. For information on the compatibility requirements for Xcode 11, see Xcode 11 Release Notes.
During installation of macOS 10.15 you might be prompted to enter your administrator password multiple times to allow installation to proceed. (51206649)
macOS frameworks are now thinned for the x86-64 architecture. Apps that execute i386 code now fail with the
EBADARCHerror code. The remaining stub frameworks are nonfunctional and exist only for compatibility purposes. (51236070)
To enhance security, AppleEvents and AppleScripts that target an app on a remote system must authenticate as the same user on the remote system. An AppleEvent that targets an app running as a different user receives a
To allow remote AppleEvents to target apps in any user session, run the following command in Terminal on the server:
Then disable and reenable Remote Apple Events in System Preferences > Sharing. (5353592)
You can now enable voice processing mode on
You can use new
AVAudiotypes to wrap a user-defined block for sending or receiving data in real-time.
A new method is available for an
AVAudiobased app to retrieve a list of all nodes attached to an
A new rendering mode in
AVAudioselects the best spatial audio rendering algorithm automatically based on the output device.
AVAudioproperty allows system sounds and haptics to play while the session is actively using audio input.
A new property,
AVAudioinforms apps which style of voice prompt they should play based on other audio activity in the system.
Session .Prompt Style
AVAudioenumeration is extended to allow apps to specify route sharing policies so their audio and video is routed to the same location as AirPlay.
Session .Route Sharing Policy
Audio Unit Extensions now support user presets that are available across all host apps.
The OpenAL framework is deprecated and remains present for compatibility purposes. Transition to
AVAudiofor spatial audio functionality.
AUGraphis deprecated in favor of
Inter-App audio is deprecated. Use Audio Units for this functionality.
Carbon component-based Audio Units are deprecated and support will be removed in a future release.
Legacy Core Audio HAL audio hardware plug-ins are no longer supported. Use Audio Server plug-ins for audio drivers.
AVPlayerclass includes two new properties,
eligible, which you can use to determine whether an HDR display is available and can play on the current device. (35938145)
For HDRPlayback Did Change Notification
AVFoundation now supports encoding video with alpha channels using HEVC. Videos encoded in this manner are broadly supported in AVFoundation APIs and by Safari within web pages. Technical details of the format can be found in the Interoperability Profile specification. (8045917)
The previously deprecated 32-bit QuickTime framework is no longer available in macOS 10.15.
The symbols for QTKit, which relied on the QuickTime framework, are still present but the classes are non-functional.
Apps using Picture Taker must specify the
NSCamerakey to access the FaceTime camera. (47916725)
Added new APIs for instantiating and modifying the built-in Core Image filters.
CIKernelinstances now support arguments with arbitrarily structured data.
CIKernelinstances now support returning a group of two by two pixels.
The integer values of
CIFormatsymbols, such as
ARGB8, have changed to a new set of values which are consistent across platforms. The former values remain supported for backward compatibility; however, you should avoid dependancies on specific numerical values.
kauthAPI has been deprecated. (50419013)
After updating to macOS Catalina 10.15 Beta 7 or later, iCloud Drive might synchronize for an extended period of time. If you notice any missing files, they can be found inside a Recovered Files folder in your home folder. (54046219)
Even when Optimize Storage is switched off, iCloud Drive might fail to automatically download all files. (50667204)
Workaround: Download files individually.
When creating a new Pages, Numbers, or Keynote document in a shared folder, you might see the message “Couldn’t connect to iCloud”. (50827963)
Workaround: Close and reopen the document.
Launch Daemons and Agents
Launch daemons and launch agents introduce new user privacy protections. Specifying privacy-sensitive files and folders in a launchd property list might not work as expected and prevent the service from running. Having
Programpointing to an executable in a privacy sensitive location is currently allowed, but may be restricted in a future release. (49702405)
To comply with the new privacy protections, resources for a launchd service must be stored in locations that aren’t privacy sensitive. If necessary, the app can set up resources during its execution rather than using launchd property list keys, making it possible to grant the app access using System Preferences > Security & Privacy > Privacy.
The following launchd property list keys are affected:
nativemight be inaccurate. Instead, get the scale factor from the local trait collection. (54009624)
MPMediamight not display the contents of your library. (51785735)
AppKit and Mac Catalyst apps are currently view-only clients of PencilKit. (51146823)
When sending Mail attachments via MessageUI, each attachment might appear as two icons when viewed by the recipient. (50369995)
Controls drawn with accent color incorrectly maintain their active color when the window is inactive. There is no need to work around this in your app. (50563638)
For Mac Catalyst apps to save to Photos Library, explicitly linking the Photos framework is required. (50781430)
Action and share extensions might exhibit visual anomalies. (51005363)
All assets at 3x scale factor are currently ignored when compiling the asset catalog for Mac Catalyst apps. Because the search begins with the universal asset, assets for a specific memory or graphics class won’t be found. For example, if you provide an image and only give a 6GB and Metal 5v1 asset, it won’t be found at runtime. It’s recommended that you provide all images as vectors to allow generation of the correct scale factors, or at minimum provide 2x versions of the assets. If you’re classifying resources based on memory and graphics families then you should provide "Any Memory" and "Any Graphics”. (51033745)
CXActioninstances might return an error. (51074735)
When creating a Mac Catalyst app from your iPad app, Xcode automatically generates a unique Mac bundle identifier. If you have an existing Mac bundle identifier you’d prefer to use, you can do so by using manual signing in Xcode. (51076014)
Follow these steps to configure your project, AppID, and provisioning profile:
Sign in to Apple Developer, then select Certificates, Identifiers, and Profiles.
In the Identifiers section, select your iOS app identifier to edit.
Check the Mac Catalyst capability to enable it, then click the Configure button.
Choose Use an existing macOS AppID and select the identifier you'd like to use from the popup menu. Click the Save button to finish editing your AppID.
In the Profiles section, click the + button to create a new profile, select ‘macOS App Development’, and click Continue.
Select your iOS AppID from the popup, click Continue, and complete the rest of the profile creation flow. When finished, click the Download button.
In Xcode, select your project to view the Project Editor and select your app’s target. Then select the Build Settings tab.
Set the Derive Mac Catalyst Product Bundle Identifier setting to No.
Expand the Product Bundle Identifier build setting to view its configurations. Next to the Debug configuration, click the + button to add a conditional value.
For the build setting condition, select Any macOS from the popup menu. Edit the value of the conditional build setting to match the macOS bundle identifier you want to use. Repeat this step for all configurations in your project.
In the Signing & Capabilities tab, uncheck Automatically manage signing.
For your macOS app, select Import Profile from the Provisioning Profile popup and then select the profile you downloaded earlier.
DOM keyboard events aren’t dispatched as expected in
WKWebwhen pressing or releasing keys. Web apps needing to track typed characters can instead listen for DOM input events. (54580414)
If your Mac contains both macOS Mojave 10.14 and macOS 10.15 volumes, you might experience issues searching in Mail. (46611310)
Workaround: While running macOS Mojave 10.14, open Terminal and execute the following command:
Reboot into macOS 10.15, open Terminal and execute the following command:
Reboot into macOS Mojave 10.14, open Terminal and execute the following command:
Depending on the size of your Mail database, it might take many hours to reindex all content.
.Cache Policy .reload Revalidating Cache Data
NSURLRequestAPIs are now available. (49660334)
.Cache Policy .reload Ignoring Local And Remote Cache Data
NWEthernetAPI doesn’t currently support VLAN interfaces.
NEPacketwill see both tagged and untagged frames arriving on physical interfaces. Depending on the Ethernet driver, VLAN tags might be processed by hardware and thus stripped off the Ethernet frames thus
NEPacketwon’t see the VLAN tag. (51275655)
Support for FTP and File URL schemes for Proxy Automatic Configuration (PAC) is removed. HTTP and HTTPS are the only supported URL schemes for PAC. This affects all PAC configurations including but not limited to configurations set using Settings, System Preferences, profiles, URLSession APIs such as
Execute Proxy Auto Configuration URL(_: _: _: _:)
The Network Kernel Extension API is now deprecated. (49284108)
The behavior of
access(2)on privacy-protected filesystem locations has been restored to that of macOS Mojave. (47309955)
Fixed an issue where turning on Curtain Mode prevented you from being able to control a remote Mac. (52900397)
Starting in macOS 10.15, the Quartz Composer framework is deprecated and remains present for compatibility purposes. Transition to frameworks such as Core Image, SceneKit, or Metal. (50911608)
Scripting Language Runtimes
Scripting language runtimes such as Python, Ruby, and Perl are included in macOS for compatibility with legacy software. Future versions of macOS won’t include scripting language runtimes by default, and might require you to install additional packages. If your software depends on scripting languages, it’s recommended that you bundle the runtime within the app. (49764202)
Use of Python 2.7 isn’t recommended as this version is included in macOS for compatibility with legacy software. Future versions of macOS won’t include Python 2.7. Instead, it’s recommended that you run
python3from within Terminal. (51097165)
NSManagednow conforms to
Observable. The new
Fetchproperty wrapper can drive views from the results of a fetch request, and
managedis now included in the environment. (50280673)
Gesture modifiers are renamed for consistency. For example,
Tap Gesture(count: perform:)
Press Action(minimum Duration: maximum Distance: _: pressing:)
Long Press Gesture(minimum Duration: maximum Distance: pressing: perform:)
Textnow has a default line limit of
nilso that it wraps by default. (51147116)
SegmentedControl is now a style of
BindableObject is replaced by the
Observableprotocol from the Combine framework. (50800624)
You can manually conform to
Observableby defining an
objectpublisher that emits before the object changes. However, by default,
objectand emits before any
@ObjectBinding is replaced by
Environmentstructure has four new properties for reading accessibility values from the environment:
Differentiate Without Color
The BindableObject protocol’s requirement is now
did, and should now be sent before the object changes rather than after it changes. This change allows for improved coalescing of change notifications. (51580731)
Rangeprotocol is extended to include a
remove(atmethod and the
Mutableprotocol is extended to include a
move(frommethod. Each new method takes
Offsets: to Offset:)
Indexinstances that you use with the
Added improved presentation modifiers:
Presented: on Dismiss: content:)
Sheet(is Presented: content:)
alert(is— along with
isin the environment — replace the previous
Updated the APIs for creating animations. The
basicanimations are now named after the curve type — such as
ease. The interpolation-based
spring(mass:animation is now
stiffness: damping: initial Velocity:)
Spring(mass: stiffness: damping: initial Velocity:)
Spring(stiffness: damping Fraction: blend Duration: timestep: idle Threshold:)
damping Fraction: blend Duration:)
interactive, depending on whether or not the animation is driven interactively. (50280375)
Spring(response: damping Fraction: blend Duration:)
You can style a
Navigationusing two new style properties:
Navigation View Style
Double. By default, navigation views on iPhone and Apple TV visually reflect a navigation stack, while on iPad and Mac, a split-view styled navigation view displays. (51636729)
Column Navigation View Style
When using the
Doublestyle, you can provide two views when creating a navigation view — the first is the master and the second is the detail. For example:
Column Navigation View Style
Apps containing SwiftUI inside a Swift package might not run on versions of iOS earlier than iOS 13. (53706729)
Workaround: When back-deploying to an OS which doesn't contain the SwiftUI framework, add the
-weakflag to the Other Linker Flags setting in the Build Settings tab. See Frameworks and Weak Linking for more information on weak linking a framework. This workaround doesn't apply when using dynamically linked Swift packages which import SwiftUI.
_framework Swift UI
The Command structure is replaced by passing selectors directly. (53187891)
NavigationDestinationLink and DynamicNavigationDestinationLink are deprecated; their functionality is now included in
The Length type is replaced by
TabbedView is now named
isenvironment value is deprecated and replaced with the more general
The StaticMember protocol is deprecated. Use protocol-conforming types directly instead. For example, use an instance of
Wheeldirectly rather than the wheel static member.(52911961)
SwiftUI APIs deprecated in previous betas are now removed. (52587863)
The retroactive conformance of
Intto the Identifiable protocol is removed. Change any code that relies on this conformance to pass \.self to the id parameter of the relevant initializer. Constant ranges of Int continue to be accepted:
However, you shouldn’t pass a range that changes at runtime. If you use a variable that changes at runtime to define the range, the list displays views according to the initial range and ignores any subsequent updates to the range.
Several extensions to the
Bindingstructure are removed. (51624798)
If you have code such as the following:
Define the following subscript on the Set structure:
If you have code such as the following:
Define the following collection type:
Then, update your code to:
relativemodifiers are deprecated. Use other modifiers like
Width: ideal Width: max Width: min Height: ideal Height: max Height: alignment:)
Command line tool support for Subversion — including
git-svn, and related commands — is no longer provided by Xcode. If you need Subversion or related command line tools, install the Command Line Tools package by running
xcode-select --install. (50266910)