diff --git a/.github/workflows/unit_tests.yml b/.github/workflows/unit_tests.yml
index 67c9fd09..ee34bd27 100644
--- a/.github/workflows/unit_tests.yml
+++ b/.github/workflows/unit_tests.yml
@@ -36,7 +36,7 @@ jobs:
       # See #400 (https://github.com/google/GoogleSignIn-iOS/issues/400)
       run: |
         pod lib lint ${{ matrix.podspec }} --verbose \
-          ${{ matrix.includePodspecFlag }} ${{ matrix.flag }}
+          ${{ matrix.includePodspecFlag }} ${{ matrix.flag }}  --sources=https://github.com/firebase/SpecsDev.git,https://github.com/firebase/SpecsStaging.git,https://cdn.cocoapods.org/
   spm-build-test:
     runs-on: ${{ matrix.os }}
     strategy:
diff --git a/GoogleSignIn.podspec b/GoogleSignIn.podspec
index 742534cd..5ebd148b 100644
--- a/GoogleSignIn.podspec
+++ b/GoogleSignIn.podspec
@@ -33,7 +33,7 @@ The Google Sign-In SDK allows users to sign in with their Google account from th
   ]
   s.ios.framework = 'UIKit'
   s.osx.framework = 'AppKit'
-  s.dependency 'AppCheckCore', '~> 11.0'
+  s.dependency 'AppCheckCore', '~> 12.0'
   s.dependency 'AppAuth', '~> 3.0'
   s.dependency 'GTMAppAuth', '~> 6.0'
   s.dependency 'GTMSessionFetcher/Core', '>= 3.3', '< 6.0'
diff --git a/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.h b/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.h
index e294273f..5a862c16 100644
--- a/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.h
+++ b/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.h
@@ -16,7 +16,7 @@
 #import <Foundation/Foundation.h>
 
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
-#import <AppCheckCore/GACAppCheckProvider.h>
+@import AppCheckCore;
 
 @class GACAppCheckToken;
 
diff --git a/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.m b/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.m
index 903fc3ff..44e54692 100644
--- a/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.m
+++ b/GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.m
@@ -16,7 +16,7 @@
 
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
 
-#import <AppCheckCore/GACAppCheckToken.h>
+@import AppCheckCore;
 
 NSUInteger const kGIDAppCheckProviderFakeError = 1;
 
diff --git a/GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.m b/GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.m
index a886eec4..58296beb 100644
--- a/GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.m
+++ b/GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.m
@@ -18,11 +18,7 @@
 
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
 
-#import <AppCheckCore/GACAppCheck.h>
-#import <AppCheckCore/GACAppCheckSettings.h>
-#import <AppCheckCore/GACAppCheckTokenResult.h>
-#import <AppCheckCore/GACAppAttestProvider.h>
-#import <AppCheckCore/GACAppCheckDebugProvider.h>
+@import AppCheckCore;
 
 #import "GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.h"
 #import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDAppCheckError.h"
@@ -117,13 +113,7 @@ - (void)prepareForAppCheckWithCompletion:(nullable GIDAppCheckPrepareCompletion)
     [self.appCheck limitedUseTokenWithCompletion:^(GACAppCheckTokenResult * _Nonnull result) {
       NSError * __block maybeError = result.error;
       @synchronized (self) {
-        if (!result.token && !result.error) {
-          maybeError = [NSError errorWithDomain:kGIDAppCheckErrorDomain
-                                           code:kGIDAppCheckUnexpectedError
-                                       userInfo:nil];
-        }
-
-        if (result.token) {
+        if (!result.error) {
           [self.userDefaults setBool:YES forKey:kGIDAppCheckPreparedKey];
         }
 
@@ -143,7 +133,7 @@ - (void)prepareForAppCheckWithCompletion:(nullable GIDAppCheckPrepareCompletion)
 - (void)getLimitedUseTokenWithCompletion:(nullable GIDAppCheckTokenCompletion)completion {
   dispatch_async(self.workerQueue, ^{
     [self.appCheck limitedUseTokenWithCompletion:^(GACAppCheckTokenResult * _Nonnull result) {
-      if (result.token) {
+      if (!result.error) {
         [self.userDefaults setBool:YES forKey:kGIDAppCheckPreparedKey];
       }
       if (completion) {
diff --git a/GoogleSignIn/Sources/GIDSignIn.m b/GoogleSignIn/Sources/GIDSignIn.m
index abbb803e..f3ca57da 100644
--- a/GoogleSignIn/Sources/GIDSignIn.m
+++ b/GoogleSignIn/Sources/GIDSignIn.m
@@ -30,7 +30,7 @@
 #import "GoogleSignIn/Sources/GIDSignInCallbackSchemes.h"
 #import "GoogleSignIn/Sources/GIDClaimsInternalOptions.h"
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
-#import <AppCheckCore/GACAppCheckToken.h>
+@import AppCheckCore;
 #import "GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.h"
 #import "GoogleSignIn/Sources/GIDAppCheck/UI/GIDActivityIndicatorViewController.h"
 #import "GoogleSignIn/Sources/GIDEMMErrorHandler.h"
diff --git a/GoogleSignIn/Tests/Unit/GIDAppCheckTest.m b/GoogleSignIn/Tests/Unit/GIDAppCheckTest.m
index 7c0610ae..61e0624e 100644
--- a/GoogleSignIn/Tests/Unit/GIDAppCheckTest.m
+++ b/GoogleSignIn/Tests/Unit/GIDAppCheckTest.m
@@ -17,7 +17,7 @@
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
 
 #import <XCTest/XCTest.h>
-#import <AppCheckCore/GACAppCheckToken.h>
+@import AppCheckCore;
 #import "GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.h"
 #import "GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.h"
 #import "GoogleSignIn/Sources/Public/GoogleSignIn/GIDAppCheckError.h"
diff --git a/GoogleSignIn/Tests/Unit/GIDSignInTest.m b/GoogleSignIn/Tests/Unit/GIDSignInTest.m
index ed959f12..658311a2 100644
--- a/GoogleSignIn/Tests/Unit/GIDSignInTest.m
+++ b/GoogleSignIn/Tests/Unit/GIDSignInTest.m
@@ -35,7 +35,7 @@
 #import "GoogleSignIn/Sources/GIDClaimsInternalOptions.h"
 
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
-#import <AppCheckCore/GACAppCheckToken.h>
+@import AppCheckCore;
 #import "GoogleSignIn/Sources/GIDAppCheck/Implementations/GIDAppCheck.h"
 #import "GoogleSignIn/Sources/GIDAppCheck/Implementations/Fake/GIDAppCheckProviderFake.h"
 #import "GoogleSignIn/Sources/GIDEMMErrorHandler.h"
@@ -426,8 +426,11 @@ - (void)testConfigureFailsNoTokenOrError {
     XCTestExpectation *configureFailsExpecation =
     [self expectationWithDescription:@"Configure fails expectation"];
 
+    NSError *expectedError = [NSError errorWithDomain:kGIDAppCheckErrorDomain
+                                                 code:kGIDAppCheckUnexpectedError
+                                             userInfo:nil];
     GIDAppCheckProviderFake *fakeProvider =
-        [[GIDAppCheckProviderFake alloc] initWithAppCheckToken:nil error:nil];
+        [[GIDAppCheckProviderFake alloc] initWithAppCheckToken:nil error:expectedError];
     GIDAppCheck *appCheck =
         [[GIDAppCheck alloc] initWithAppCheckProvider:fakeProvider
                                          userDefaults:_testUserDefaults];
diff --git a/Package.swift b/Package.swift
index bad348a0..119f7842 100644
--- a/Package.swift
+++ b/Package.swift
@@ -44,9 +44,10 @@ let package = Package(
     .package(
       url: "https://github.com/openid/AppAuth-iOS.git",
       from: "3.0.0"),
-    .package(
-      url: "https://github.com/google/app-check.git",
-      from: "11.0.0"),
+//    .package(
+//      url: "https://github.com/google/app-check.git",
+//      from: "11.0.0"),
+    .package(url: "https://github.com/google/app-check.git", branch: "pb-swift"),
     .package(
       url: "https://github.com/google/GTMAppAuth.git",
       from: "6.0.0"),