This file can be downloaded as part of milnupdate.tbz.

Miln Update

Miln Update adds a secure update mechanism to sandboxed and notarised macOS applications.

Miln Update includes UpdateCore and UpdateKit. UpdateCore provides the core functionality of discovering and applying updates. UpdateKit provides a ready-to-use user interface.

To learn more about Miln Update visit

Miln Update is published under the Artistic License 2.0 by Graham Miln.

Getting Started with UpdateKit

Let’s create a macOS application in Xcode, add the update frameworks, and configure the essential settings:

Create a New Application

  1. Launch

  2. Select the menu item: File (menu) > New > Project…

  3. Choose the project template: macOS > App

  4. Choose the options for your new project:

    1. Product Name: MyExampleApp
    2. Team: Your Team Name

    You can choose Objective-C or Swift. Miln Update works with both development languages.

Add the Frameworks

  1. Download milnupdate.tbz and expand the downloaded archive

  2. Within the Finder, place the expanded milnupdate folder into the project’s MyExampleApp folder:

  3. Within Xcode, add the framework projects updatecore and updatekit to your application project. Use the menu item: File (menu) > Add Files to “MyExampleApp”… and select the Xcode project files:

    • MyExampleApp/milnupdate/frameworks/updatecore/updatecore.xcodeproj
    • MyExampleApp/milnupdate/frameworks/updatekit/updatekit.xcodeproj
  4. Within Xcode’s Project Navigator, select the top item, MyExampleApp

  5. Within Targets select MyExampleApp

  6. With the MyExampleApp target, select Build Phases

  7. Expand the Dependencies build phase and use the + button to add two frameworks as dependencies:

    • UpdateCore
    • UpdateKit
  8. Select the menu item: Editor > Add Build Phase > Add Copy Files Build Phase

  9. Expand the new Copy Files build phase and change Destination to Frameworks

  10. With the Copy Files build phase, use the + button to copy the two frameworks into the application:

    • UpdateCore.framework
    • UpdateKit.framework

Configure Code Signing

  1. Select the menu item: File (menu) > New > File…

  2. Choose the file template: macOS > Configuration Settings File

  3. Save the file as milnupdate.xcconfig in the folder containing the milnupdate folder:

  4. Within milnupdate.xcconfig copy, paste, and modify the settings below:

    MILNUPDATE_APP_BUNDLE = com.example.myexampleapp
    CODE_SIGN_IDENTITY[sdk=*][arch=*] = Developer ID Application

    The critical setting to modify is the DEVELOPMENT_TEAM value. This is unique to your Apple Developer certificate. These settings are overriding defaults in MyExampleApp/milnupdate/frameworks/updatecore/updatecore.xcconfig.

Calling UpdateKit

Depending on the development language used, the syntax for initialising UpdateKit differs slightly.

UpdateKit needs to know where to find updates. Updates are discovered using a text based Really Simple Syndication (RSS) file. The URL used to check for updates is called the Discovery URL.

Calling UpdateKit with Swift

Within your project’s application delegate, AppDelegate.swift, make these changes:

  1. Import the UpdateKit framework:

    import UpdateKit
  2. Add and initialise a class property:

    var updater: UKSoftwareUpdater! = UKSoftwareUpdater.init(discoveryURL: URL.init(string: "")!)

Calling UpdateKit with Objective-C

Within your project’s application delegate, AppDelegate.m, make these changes:

  1. Import the UpdateKit framework:

    @import UpdateKit;
  2. Add a class property:

    @property (strong) UKSoftwareUpdater* updater;
  3. Within the applicationDidFinishLaunching method, create the updater:

    - (void)applicationDidFinishLaunching:(NSNotification*) aNotification {
        self.updater = [[UKSoftwareUpdater alloc] initWithDiscoveryURL:[NSURL URLWithString:@""]];

Build and Run

Your project is now ready to build and run.

You may encounter errors where Xcode can not initially find your milnupdate.xcconfig file. To fix this, quit and relaunch Xcode, then select the menu item: Product > Clean Build Folder.

Building with xcodebuild

When building with xcodebuild, provide an absolute path for SYMROOT. This will fix problems with missing modules:

/usr/bin/xcrun xcodebuild SYMROOT=[/an/absolute/path]

Publishing an Update

An update requires two parts: an RSS feed to discover updates and a package to download. These two files are distributed using a web server.

Create a Discovery RSS Feed

  1. Copy and modify the XML file milnupdate/samples/minimal.xml. The essential values to change are the enclosure attributes for version and url.

The version attribute is compared to the application’s Info.plist CFBundleVersion value.

The url attribute must link to an Installer package containing the update to install.

Create a Package for Distribution

Updates are distributed as flat file macOS Installer packages (.pkg files). Miln Update includes a tool to create these packages from an application.

  1. Use the tool to create a package containing your application:

    milnupdate/tools/ --app [path/to/application]
  2. Digitally sign the package using a Developer ID Installer Certificate from Apple:

    /usr/bin/productsign --sign <identity> myexampleapp-1.0.pkg myexampleapp-1.0-signed.pkg
  3. Ask Apple to notarise the signed package:

    xcrun altool --notarize-app --file myexampleapp-1.0-signed.pkg

The signed package is now ready for distribution.

Upload the Files

Upload the signed package and discovery file to a web server. The web server must serve the discovery file for requests made to the URL provided to UKSoftwareUpdater in your application’s code.

Ready to Test

The final step is to test your new application and update.

The application will automatically check for updates once a week. When a new update is discovered the application will prompt the user to install.

Getting Help and Support

Support contracts are available for help with integrating and customising Miln Update and for preparing update packages.