Siren 3.2.0

Siren 3.2.0

LangLanguage SwiftSwift
License MIT
ReleasedLast Release Dec 2017
SPMSupports SPM

Maintained by Aaron Brager, Arthur Ariel Sabintsev.




Test Targets417
Watch Apps2
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Pull Requests1


LOCLines of Code 589

Siren 3.2.0

  • By
  • Arthur Ariel Sabintsev and Aaron Brager

Siren 🚨

Notify users when a new version of your app is available and prompt them to upgrade.

Swift Support

BuddyBuild CocoaPods Carthage Compatible SwiftPM Compatible CocoaPods CocoaPods

Table of Contents


Siren checks a user's currently installed version of your iOS app against the version that is currently available in the App Store.

If a new version is available, an alert can be presented to the user informing them of the newer version, and giving them the option to update the application. Alternatively, Siren can notify your app programmatically, enabling you to inform the user through alternative means, such as a custom interface.

  • Siren is built to work with the Semantic Versioning system.
    • Semantic Versioning is a three number versioning system (e.g., 1.0.0)
    • Siren also supports two-number versioning (e.g., 1.0) and four-number versioning (e.g.,
  • Siren is actively maintained by Arthur Sabintsev and Aaron Brager

README Translations



  • The left picture forces the user to update the app.
  • The center picture gives the user the option to update the app.
  • The right picture gives the user the option to skip the current update.
  • These options are controlled by the Siren.AlertType enum.

Installation Instructions

Swift Version Branch Name Will Continue to Receive Updates?
4.0 master Yes
3.2 swift3.2 No
3.1 swift3.1 No
2.3 swift2.3 No


For Swift 4 support:

pod 'Siren'

For Swift 3.2 support:

pod 'Siren', :git => '', :branch => 'swift3.2'

For Swift 3.1 support:

pod 'Siren', :git => '', :branch => 'swift3.1'

For Swift 2.3 support:

pod 'Siren', :git => '', :branch => 'swift2.3'


For Swift 4 support:

github "ArtSabintsev/Siren"

For Swift 3.2 support:

github "ArtSabintsev/Siren", "swift3.2"

For Swift 3.1 support:

github "ArtSabintsev/Siren", "swift3.1"

For Swift 2.3 support:

github "ArtSabintsev/Siren", "swift2.3"

Swift Package Manager

.Package(url: "", majorVersion: 3)

Example Code

Below is some commented sample code. Adapt this to meet your app's needs.

For a full list of optional settings/preferences, please refer to in the Sample Project.

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
	/* Siren code should go below window?.makeKeyAndVisible() */

	  // Siren is a singleton
	  let siren = Siren.shared

	  // Optional: Defaults to .option
	  siren.alertType = <#Siren.AlertType_Enum_Value#>

	  // Optional: Change the various UIAlertController and UIAlertAction messaging. One or more values can be changes. If only a subset of values are changed, the defaults with which Siren comes with will be used.
      siren.alertMessaging = SirenAlertMessaging(updateTitle: "New Fancy Title",
                                                 updateMessage: "New message goes here!",
                                                 updateButtonMessage: "Update Now, Plz!?",
                                                 nextTimeButtonMessage: "OK, next time it is!",
                                                 skipVersionButtonMessage: "Please don't push skip, please don't!")

	  // Optional: Set this variable if you would only like to show an alert if your app has been available on the store for a few days.
	  // This default value is set to 1 to avoid this issue:
	  // To show the update immediately after Apple has updated their JSON, set this value to 0. Not recommended due to aforementioned reason in
	  siren.showAlertAfterCurrentVersionHasBeenReleasedForDays = 3

	  // Replace .immediately with .daily or .weekly to specify a maximum daily or weekly frequency for version checks.
		// DO NOT CALL THIS METHOD IN didFinishLaunchingWithOptions IF YOU ALSO PLAN TO CALL IT IN applicationDidBecomeActive.
    siren.checkVersion(checkType: .immediately)

    return true

func applicationDidBecomeActive(application: UIApplication) {
	    Perform daily (.daily) or weekly (.weekly) checks for new version of your app.
	    Useful if user returns to your app from the background after extended period of time.
    	 Place in applicationDidBecomeActive(_:).	*/

    Siren.shared.checkVersion(checkType: .daily)

func applicationWillEnterForeground(application: UIApplication) {
      Useful if user returns to your app from the background after being sent to the
      App Store, but doesn't update their app before coming back to your app.

      ONLY USE WITH Siren.AlertType.immediately

    Siren.shared.checkVersion(checkType: .immediately)

And you're all set!

Prompting for Updates without Alerts

Some developers may want to display a less obtrusive custom interface, like a banner or small icon. To accomplish this, you can disable alert presentation by doing the following:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
	siren.delegate = self
	siren.alertType = .none

extension AppDelegate: SirenDelegate {
	// Returns a localized message to this delegate method upon performing a successful version check
    func sirenDidDetectNewVersionWithoutAlert(message: String) {

Siren will call the sirenDidDetectNewVersionWithoutAlert(message: String) delegate method, passing a localized, suggested update string suitable for display. Implement this method to display your own messaging, optionally using message.

Granular Version Update Management

If you would like to set a different type of alert for revision, patch, minor, and/or major updates, simply add one or all of the following optional lines to your setup before calling the checkVersion() method:

	/* Siren defaults to Siren.AlertType.option for all updates */
	siren.shared.revisionUpdateAlertType = <#Siren.AlertType_Enum_Value#>
	siren.shared.patchUpdateAlertType = <#Siren.AlertType_Enum_Value#>
	siren.shared.minorUpdateAlertType = <#Siren.AlertType_Enum_Value#>
	siren.shared.majorUpdateAlertType = <#Siren.AlertType_Enum_Value#>

Optional Delegate and Delegate Methods

Six delegate methods allow you to handle or track the user's behavior. Each method has a default, empty implementation, effectively making each of these methods optional.

public protocol SirenDelegate: class {
    func sirenDidShowUpdateDialog(alertType: Siren.AlertType)  // User presented with update dialog
    func sirenUserDidLaunchAppStore()                          // User did click on button that launched App
    func sirenUserDidSkipVersion()                             // User did click on button that skips version update
    func sirenUserDidCancel()                                  // User did click on button that cancels update dialog
    func sirenDidFailVersionCheck(error: Error)                // Siren failed to perform version check (may return system-level error)
    func sirenDidDetectNewVersionWithoutAlert(message: String) // Siren performed version check and did not display alert


Siren is localized for

  • Arabic
  • Armenian
  • Basque
  • Chinese (Simplified and Traditional)
  • Croatian
  • Czech
  • Danish
  • Dutch
  • English
  • Estonian
  • Finnish
  • French
  • German
  • Greek
  • Hebrew
  • Hungarian
  • Indonesian
  • Italian
  • Japanese
  • Korean
  • Latvian
  • Lithuanian
  • Malay
  • Norwegian (Bokmål)
  • Persian (Afghanistan, Iran, Persian)
  • Polish
  • Portuguese (Brazil and Portugal)
  • Russian
  • Serbian (Cyrillic and Latin)
  • Slovenian
  • Spanish
  • Swedish
  • Thai
  • Turkish
  • Ukrainian
  • Urdu
  • Vietnamese

You may want the update dialog to always appear in a certain language, ignoring iOS's language setting (e.g. apps released in a specific country).

You can enable it like so:

Siren.shared.forceLanguageLocalization = Siren.LanguageType.<#Siren.LanguageType_Enum_Value#>

Device Compatibility

If an app update is available, Siren checks to make sure that the version of iOS on the user's device is compatible with the one that is required by the app update. For example, if a user has iOS 9 installed on their device, but the app update requires iOS 10, an alert will not be shown. This takes care of the false positive case regarding app updating.

Testing Siren

Temporarily change the version string in Xcode (within the .xcodeproj) to an older version than the one that's currently available in the App Store. Afterwards, build and run your app, and you should see the alert.

If you currently don't have an app in the store, change your bundleID to one that is already in the store. In the sample app packaged with this library, we use the iTunes Connect Mobile app's bundleID:

For your convenience, you may turn on debugging statements by setting self.debugEnabled = true before calling the checkVersion() method.

App Store Submissions

The App Store reviewer will not see the alert. The version in the App Store will always be older than the version being reviewed.

Phased Releases

In 2017, Apple announced the ability to rollout app updates gradually (a.k.a. Phased Releases). Siren will continue to work as it has in the past, presenting an update modal to all users. If you opt-in to a phased rollout for a specific version, you have a few choices:

  • You can leave Siren configured as normal. Phased rollout will continue to auto-update apps. Since all users can still manually update your app directly, Siren will ignore the phase rollout and will prompt users to update.
  • You can set showAlertAfterCurrentVersionHasBeenReleasedForDays to 7, and Siren will not prompt any users until the latest version is 7 days old, after phased rollout is complete.
  • You can remotely disable Siren until the rollout is done using your own API / backend logic.

Words of Caution

Occasionally, the iTunes JSON will update faster than the App Store CDN, meaning the JSON may state that the new version of the app has been released, while no new binary is made available for download via the App Store. It is for this reason that Siren will, by default, wait 24 hours after the JSON has been updated to prompt the user to update. To change the default setting, please modify the value of showAlertAfterCurrentVersionHasBeenReleasedForDays.


  • Objective-C (iOS)
    • Harpy
    • Siren was ported from Harpy, as Siren and Harpy are maintained by the same developer.
  • Java (Android)
  • React Native (iOS)

Created and maintained by

Arthur Ariel Sabintsev & Aaron Brager