Add support for the new FCM registration ID. by leojaygoogle · Pull Request #16133 · firebase/firebase-ios-sdk

leojaygoogle · 2026-04-29T00:20:38Z

No description provided.

It defaults to NO. When enabled, FCM will not generate an FCM registration token, but an FID instead.

…anagement system. Currently, the FCM SDK calls the `https://fcmtoken.googleapis.com/register` backend to register an FCM V4 registration token. Going forward, we'd like to deprecate this token and use FID instead.

Once `unregister()` is called successfully and auto-init is disabled, Sending a push notification to the FID will result in an `UNREGISTERED` error.

This method is similar to `messaging(_:didReceiveRegistrationToken:)`, but will be called instead when `isInstallationIdEnabled` is `YES`.

gemini-code-assist · 2026-04-29T00:20:42Z

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…hods

Doris-Ge

Does our existing implementation listen for a FID change via a listener and re-register on a change? If not, we may want to add that.

I'm still reviewing the PR, but I'd like to give some early feedback in case you want to address or discuss it. Since I'm not familiar with Swift, I need more time for a full review. Sorry about that!

Doris-Ge · 2026-04-29T19:21:45Z

 - (void)updateDefaultFCMToken:(NSString *)defaultFCMToken {
  NSString *oldToken = self.tokenManager.defaultFCMToken;
  NSString *newToken = defaultFCMToken;
  if ([self.tokenManager hasTokenChangedFromOldToken:oldToken toNewToken:newToken]) {


Could we always invoke the callback even if the FID is not changed after a backend sync (we don't need to invoke the callback on every app start if the cached FID is not expired and it's still the same), considering that unlike a token, the FID is not going to be changed after a subsequent register() call following an unregister() call?

This change would enable developers to regularly sync the FID with their app servers, allowing for easier self-recovery during incidents. For instance, if a 404 error is mistakenly returned for a send request, leading an app server to delete a FID, invoking the callback regardless of a change would allow the server to re-acquire the FID automatically.

I can do that. Do you want to limit this behavior to FID only or do you want the callback to be called no matter what value isInstallationIdEnabled is?

FID only. Thanks!

Discussed offline and we have decided to not change the existing behavior.

Doris-Ge · 2026-04-30T01:20:10Z

Can we update FIRMessagingTest.m to test changes in this file? Some test cases to consider:

When isInstallationIdEnabled is true

A call to register() can successfully invoke didReceiveRegistration() regardless whether the same FID has been registered or not and regardless whether isAutoInit is enabled or not.

A call to unregister() should invoke didUnregister() and leave the app as unregistered.

When isAutoInit=true, didReceiveRegistration() is invoked on app start when a new FID is registered or the registered FID has expired or the FID is changed.

token/deleteToken should throw an error

retrieveFCMTokenForSenderID/deleteFCMTokenForSenderID should throw an error

When isInstallationIdEnabled is false

register()/unregister() should throw an error.

I will add tests for the first 3 items. Regarding throwing exceptions, our style guide suggests avoiding them. go/objc-style#avoid-throwing-exceptions.

Sounds good! Good to know that.

…okenFetchOperation. It's not used by other classes.

…didUnregister is called only when the deletion succeeded.

Doris-Ge · 2026-05-11T06:39:44Z

+      @"apns_token" : apnsTokenString,
+      @"app_version" : appVersion,
+      @"apns_environment" : apnsEnvironment
+    },


I've proposed adding the bundle_id field to the backend API in cl/913512427. Can we start passing it here?It should be fine, even in the worst-case scenario where the API Council disapproves the CL.

Discussed offline. we will add that later.

Doris-Ge · 2026-05-12T00:57:58Z

+                            @"No Sender ID is available to register");
+    return;
+  }
+  [self setupInstallationIDObserver];


Shall we clear the observer during unregister()? If an app disables the auto init and calls unregister() after calling register(), not clearing the observer may automatically register the app with backend on FID changes, which may be unexpected for developers.

Also, it seems the observer is only set up in the register() method. Calling register() is optional for apps that enable auto-init. We should make sure that those apps can also re-register on FID changes.

Consider setting up this observer regardlessly but only re-register when the app is registered as Eldhose did for Android: https://screenshot.googleplex.com/xmAGrSTKbyRMpSm.

It tests that when `FirebaseMessaging.isInstallationIdEnabled` is `YES`, calling `register()` triggers a V1 registration API HTTP request. After receiving the registered FID, the message delegate's `didReceiveRegistration` should be called.

…register`. So that it doesn't depend on the `register` being called.

wiz-9635d3485b · 2026-05-13T16:00:17Z

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…IdEnabled`

leojaygoogle added 8 commits April 17, 2026 15:29

Introduce new Info.plist key FirebaseMessagingInstallationIdEnabled.

12a6ad8

It defaults to NO. When enabled, FCM will not generate an FCM registration token, but an FID instead.

Add retry logic on network error and backend 5xx error.

b442d42

Implement the FCM FID unregistration operation.

fe49a75

Once `unregister()` is called successfully and auto-init is disabled, Sending a push notification to the FID will result in an `UNREGISTERED` error.

Add didReceiveRegistration delegate method.

f1294be

This method is similar to `messaging(_:didReceiveRegistrationToken:)`, but will be called instead when `isInstallationIdEnabled` is `YES`.

Update the sample app to handle the new registration ID.

8c0ba25

Update CHANGELOG

b471f82

Style update.

4b72a42

danger-firebase-ios Bot added api: messaging public-api-change labels Apr 29, 2026

Doris-Ge reviewed Apr 29, 2026

View reviewed changes

Comment thread FirebaseMessaging/Sources/Public/FirebaseMessaging/FIRMessaging.h Outdated

leojaygoogle added 3 commits April 29, 2026 11:33

Use the internal FirebaseInstallations header file.

c28628b

Rename registrationId to installationId in messaging delegate met…

e7aeac8

…hods

Update copyright header to include LLC

836b697

Doris-Ge reviewed Apr 29, 2026

View reviewed changes

Fix various compile warnings.

dff8587

Doris-Ge reviewed Apr 30, 2026

View reviewed changes

leojaygoogle added 7 commits April 30, 2026 17:09

Add an FIRMessagingErrorCode to indicate installation related errors.

503c5b6

Move heartbeatLogger from FIRMessagingTokenOperation to FIRMessagingT…

c12d985

…okenFetchOperation. It's not used by other classes.

Fix style warnings and address review comments.

1d4c3f8

Mark authorizedEntity as nullable.

e984467

Add FIRMessagingInstallationIdUnregisteredNotification and make sure …

125dac3

…didUnregister is called only when the deletion succeeded.

Monitor FID change events and register the new FID when it happens.

d95a204

Delete unused methods.

f7cea1d

Doris-Ge reviewed May 11, 2026

View reviewed changes

Doris-Ge reviewed May 12, 2026

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leojaygoogle added 3 commits May 13, 2026 01:40

Add testUnregisterNotifiesDelegateWhenInstallationIdEnabled

26c94d2

Move installationIDObserver setup to the start method, instead of `…

6093f94

…register`. So that it doesn't depend on the `register` being called.

Fix test ordering failure in FIRMessagingTokenInfoTest.

e7433b8

Add test `testAppStartNotifiesDelegateWhenBothAutoInitAndInstallation…

77ad7f5

…IdEnabled`

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Doris-Ge May 12, 2026 •

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