diff --git a/.github/workflows/abtesting.yml b/.github/workflows/abtesting.yml
index a8701041b72..a52070bdf10 100644
--- a/.github/workflows/abtesting.yml
+++ b/.github/workflows/abtesting.yml
@@ -51,7 +51,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       env:
         LEGACY: true
@@ -86,7 +86,7 @@ jobs:
       run: scripts/decrypt_gha_secret.sh scripts/gha-encrypted/qs-abtesting.plist.gpg \
           quickstart-ios/abtesting/GoogleService-Info.plist "$plist_secret"
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Build swift quickstart
       env:
         LEGACY: true
@@ -116,7 +116,7 @@ jobs:
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: PodLibLint ABTesting Cron
       run: |
         scripts/third_party/travis/retry.sh scripts/pod_lib_lint.rb \
diff --git a/.github/workflows/client_app.yml b/.github/workflows/client_app.yml
index 150d879edca..8c4f72c4c27 100644
--- a/.github/workflows/client_app.yml
+++ b/.github/workflows/client_app.yml
@@ -27,12 +27,16 @@ jobs:
   client-app-spm:
     if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
     strategy:
-      # TODO: Add Xcode matrix when Xcode 16 is ubiquitous on CI runners.
       matrix:
         #TODO(ncooke3): Add multi-platform support: tvOS, macOS, catalyst
         platform: [iOS]
         scheme: [ClientApp]
         os: [macos-14, macos-15]
+        include:
+          - os: macos-14
+            xcode: Xcode_16.2
+          - os: macos-15
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -40,8 +44,8 @@ jobs:
         with:
           cache_key: ${{ matrix.os }}
       - name: Xcode
-        run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
-      - name: Build Client App –– ${{ matrix.platform }}
+        run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app/Contents/Developer
+      - name: Build Client App - ${{ matrix.platform }}
         run: scripts/third_party/travis/retry.sh ./scripts/build.sh ${{ matrix.scheme }} ${{ matrix.platform }} xcodebuild
 
   client-app-spm-source-firestore:
@@ -50,12 +54,16 @@ jobs:
         FIREBASECI_USE_LATEST_GOOGLEAPPMEASUREMENT: 1
         FIREBASE_SOURCE_FIRESTORE: 1
       strategy:
-        # TODO: Add Xcode matrix when Xcode 16 is ubiquitous on CI runners.
         matrix:
           #TODO(ncooke3): Add multi-platform support: tvOS, macOS, catalyst
           platform: [iOS]
           scheme: [ClientApp]
           os: [macos-14, macos-15]
+          include:
+            - os: macos-14
+              xcode: Xcode_16.2
+            - os: macos-15
+              xcode: Xcode_16.4
       runs-on: ${{ matrix.os }}
       steps:
         - uses: actions/checkout@v4
@@ -63,18 +71,22 @@ jobs:
           with:
             cache_key: ${{ matrix.os }}
         - name: Xcode
-          run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
-        - name: Build Client App –– ${{ matrix.platform }}
+          run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app/Contents/Developer
+        - name: Build Client App - ${{ matrix.platform }}
           run: scripts/third_party/travis/retry.sh ./scripts/build.sh ${{ matrix.scheme }} ${{ matrix.platform }} xcodebuild
 
   client-app-cocoapods:
     # Don't run on private repo unless it is a PR.
     if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
     strategy:
-      # TODO: Add Xcode matrix when Xcode 16 is ubiquitous on CI runners.
       matrix:
         scheme: [ClientApp-CocoaPods]
         os: [macos-14, macos-15]
+        include:
+          - os: macos-14
+            xcode: Xcode_16.2
+          - os: macos-15
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -85,7 +97,7 @@ jobs:
       - name: Setup Bundler
         run: scripts/setup_bundler.sh
       - name: Xcode
-        run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+        run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app/Contents/Developer
       - name: Prereqs
         run: scripts/install_prereqs.sh ClientApp iOS xcodebuild
       - name: Build
diff --git a/.github/workflows/common.yml b/.github/workflows/common.yml
index 1a82d76b36f..b79680f09b4 100644
--- a/.github/workflows/common.yml
+++ b/.github/workflows/common.yml
@@ -67,7 +67,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Xcode
-        run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+        run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
       - name: Generate Swift Package.resolved
         id: swift_package_resolve
         run: swift package resolve
@@ -104,10 +104,6 @@ jobs:
         key: ${{needs.spm-package-resolved.outputs.cache_key}}
     - name: Xcode
       run: sudo xcode-select -s /Applications/${{ matrix.xcode }}.app/Contents/Developer
-    - name: Install visionOS, if needed.
-      if: matrix.platform == 'visionOS'
-      run: ls $(xcode-select -p)/Platforms/XROS.platform || \
-        { xcodebuild -downloadPlatform visionOS }
     - name: Run setup command, if needed.
       if: inputs.setup_command != ''
       run: ${{ inputs.setup_command }}
diff --git a/.github/workflows/common_catalyst.yml b/.github/workflows/common_catalyst.yml
index 6948e4e3197..da3911b064c 100644
--- a/.github/workflows/common_catalyst.yml
+++ b/.github/workflows/common_catalyst.yml
@@ -38,7 +38,7 @@ jobs:
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - uses: nick-fields/retry@ce71cc2ab81d554ebbe88c79ab5975992d79ba08 # v3
       with:
         timeout_minutes: 120
diff --git a/.github/workflows/core_extension.yml b/.github/workflows/core_extension.yml
index 15b86f38538..cc9d602f15d 100644
--- a/.github/workflows/core_extension.yml
+++ b/.github/workflows/core_extension.yml
@@ -39,7 +39,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: PodLibLint CoreInternal Cron
diff --git a/.github/workflows/core_internal.yml b/.github/workflows/core_internal.yml
index d1b8dd6cf73..db3d565f69f 100644
--- a/.github/workflows/core_internal.yml
+++ b/.github/workflows/core_internal.yml
@@ -54,7 +54,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: PodLibLint CoreInternal Cron
diff --git a/.github/workflows/crashlytics.yml b/.github/workflows/crashlytics.yml
index a32d474a61b..0f5f2cb5643 100644
--- a/.github/workflows/crashlytics.yml
+++ b/.github/workflows/crashlytics.yml
@@ -53,7 +53,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh crashlytics
       env:
@@ -86,7 +86,7 @@ jobs:
       with:
         python-version: '3.11'
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh crashlytics
       env:
@@ -130,7 +130,7 @@ jobs:
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - uses: nick-fields/retry@ce71cc2ab81d554ebbe88c79ab5975992d79ba08 # v3
       with:
         timeout_minutes: 120
diff --git a/.github/workflows/database.yml b/.github/workflows/database.yml
index 928c3bf28ad..24998fa0deb 100644
--- a/.github/workflows/database.yml
+++ b/.github/workflows/database.yml
@@ -84,7 +84,7 @@ jobs:
       run: scripts/decrypt_gha_secret.sh scripts/gha-encrypted/qs-database.plist.gpg \
           quickstart-ios/database/GoogleService-Info.plist "$plist_secret"
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Test objc quickstart
       run: ([ -z $plist_secret ] || scripts/third_party/travis/retry.sh scripts/test_quickstart.sh Database false)
     - name: Test swift quickstart
@@ -106,7 +106,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: PodLibLint database Cron
diff --git a/.github/workflows/firebase_app_check.yml b/.github/workflows/firebase_app_check.yml
index ff30db15a66..cd9f8eac577 100644
--- a/.github/workflows/firebase_app_check.yml
+++ b/.github/workflows/firebase_app_check.yml
@@ -58,7 +58,7 @@ jobs:
       with:
         cache_key: ${{ matrix.diagnostics }}
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Initialize xcodebuild
       run: scripts/setup_spm_tests.sh
     - name: iOS Unit Tests
@@ -84,7 +84,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: PodLibLint FirebaseAppCheck Cron
diff --git a/.github/workflows/firebasepod.yml b/.github/workflows/firebasepod.yml
index 8f7fd3af5ef..f1e228b7f24 100644
--- a/.github/workflows/firebasepod.yml
+++ b/.github/workflows/firebasepod.yml
@@ -34,7 +34,7 @@ jobs:
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Prereqs
       run: scripts/install_prereqs.sh FirebasePod iOS
     - name: Build
diff --git a/.github/workflows/firestore.yml b/.github/workflows/firestore.yml
index 3e927287a2e..d3f61e67b4a 100644
--- a/.github/workflows/firestore.yml
+++ b/.github/workflows/firestore.yml
@@ -375,6 +375,9 @@ jobs:
 
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
 
+    - name: Select Xcode
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
+
     - name: Setup build
       run:  scripts/install_prereqs.sh Firestore ${{ matrix.target }} xcodebuild
 
@@ -578,7 +581,7 @@ jobs:
       with:
         cache_key: ${{ matrix.target }}
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Initialize xcodebuild
       run: scripts/setup_spm_tests.sh
     - name: Build Test - Binary
diff --git a/.github/workflows/inappmessaging.yml b/.github/workflows/inappmessaging.yml
index 6650fbb8fc9..feb26e72c65 100644
--- a/.github/workflows/inappmessaging.yml
+++ b/.github/workflows/inappmessaging.yml
@@ -46,7 +46,7 @@ jobs:
 # TODO(#8682): Reenable iPad after fixing Xcode 13 test failures.
 #        platform: [iOS, iPad]
         platform: [iOS]
-        xcode: [Xcode_16.2]
+        xcode: [Xcode_16.4]
     steps:
     - uses: actions/checkout@v4
     - uses: mikehardy/buildcache-action@c87cea0ccd718971d6cc39e672c4f26815b6c126
@@ -78,7 +78,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: PodLibLint InAppMessaging Cron
@@ -98,7 +98,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh inappmessaging
     - name: install secret googleservice-info.plist
diff --git a/.github/workflows/installations.yml b/.github/workflows/installations.yml
index cf4f6795b18..2b149918f0a 100644
--- a/.github/workflows/installations.yml
+++ b/.github/workflows/installations.yml
@@ -56,7 +56,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh installations
     - name: Copy mock plist
@@ -78,7 +78,7 @@ jobs:
       with:
         python-version: '3.11'
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh installations
     - name: Copy mock plist
@@ -112,7 +112,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Configure test keychain
diff --git a/.github/workflows/messaging.yml b/.github/workflows/messaging.yml
index 838ce5fe4d9..db9d8f8ccac 100644
--- a/.github/workflows/messaging.yml
+++ b/.github/workflows/messaging.yml
@@ -89,7 +89,7 @@ jobs:
       matrix:
         include:
           - os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
@@ -122,7 +122,7 @@ jobs:
       with:
         python-version: '3.11'
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh messaging
     - name: Install Secret GoogleService-Info.plist
@@ -150,7 +150,7 @@ jobs:
         os: [macos-14, macos-15]
         include:
           - os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
             tests: --test-specs=unit
           - os: macos-14
             xcode: Xcode_16.2
@@ -187,7 +187,7 @@ jobs:
     - name: Prereqs
       run: scripts/install_prereqs.sh MessagingSample iOS
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Build
       run: ([ -z $plist_secret ] || scripts/build.sh MessagingSample iOS)
 
@@ -212,7 +212,7 @@ jobs:
     - name: Prereqs
       run: scripts/install_prereqs.sh SwiftUISample iOS
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Build
       run: ([ -z $plist_secret ] || scripts/build.sh SwiftUISample iOS)
 
@@ -237,7 +237,7 @@ jobs:
     - name: Prereqs
       run: scripts/install_prereqs.sh MessagingSampleStandaloneWatchApp watchOS
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Build
       run: ([ -z $plist_secret ] || scripts/build.sh MessagingSampleStandaloneWatchApp watchOS)
 
diff --git a/.github/workflows/mlmodeldownloader.yml b/.github/workflows/mlmodeldownloader.yml
index 3eddabeadec..931c8edda79 100644
--- a/.github/workflows/mlmodeldownloader.yml
+++ b/.github/workflows/mlmodeldownloader.yml
@@ -57,7 +57,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Configure test keychain
@@ -83,7 +83,7 @@ jobs:
         cache_key: build-test${{ matrix.os }}
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Install GoogleService-Info.plist
diff --git a/.github/workflows/performance.yml b/.github/workflows/performance.yml
index b1073dfd11f..61c08473772 100644
--- a/.github/workflows/performance.yml
+++ b/.github/workflows/performance.yml
@@ -60,7 +60,7 @@ jobs:
         cache_key: ${{ matrix.target }}${{ matrix.test }}
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: Install xcpretty
@@ -87,7 +87,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh performance
     - name: Install Secret GoogleService-Info.plist
@@ -113,7 +113,7 @@ jobs:
       with:
         python-version: '3.11'
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup quickstart
       run: scripts/setup_quickstart.sh performance
     - name: Install Secret GoogleService-Info.plist
@@ -145,7 +145,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup Bundler
       run: scripts/setup_bundler.sh
     - name: PodLibLint Performance Cron
diff --git a/.github/workflows/prerelease.yml b/.github/workflows/prerelease.yml
index 2cb87713f68..6bdc3749b3f 100644
--- a/.github/workflows/prerelease.yml
+++ b/.github/workflows/prerelease.yml
@@ -242,7 +242,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup testing repo and quickstart
       run: BOT_TOKEN="${botaccess}" scripts/setup_quickstart.sh Authentication prerelease_testing
     - name: Install Secret GoogleService-Info.plist
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index de6631fc6b4..531cc021b2c 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -188,7 +188,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - name: Setup testing repo and quickstart
       run: BOT_TOKEN="${botaccess}" scripts/setup_quickstart.sh Authentication nightly_release_testing
     - name: Install Secret GoogleService-Info.plist
diff --git a/.github/workflows/sessions-integration-tests.yml b/.github/workflows/sessions-integration-tests.yml
index 4d11e4dc065..ccc8d9f15fd 100644
--- a/.github/workflows/sessions-integration-tests.yml
+++ b/.github/workflows/sessions-integration-tests.yml
@@ -31,7 +31,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Xcode
-      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+      run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
     - uses: mikehardy/buildcache-action@c87cea0ccd718971d6cc39e672c4f26815b6c126
       with:
         cache_key: sessions-integration-tests
diff --git a/.github/workflows/spm.yml b/.github/workflows/spm.yml
index 5b807927410..a1227e2ef1c 100644
--- a/.github/workflows/spm.yml
+++ b/.github/workflows/spm.yml
@@ -98,7 +98,7 @@ jobs:
           - os: macos-14
             xcode: Xcode_16.2
           - os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
@@ -127,7 +127,7 @@ jobs:
         target: [tvOS, macOS, catalyst]
         include:
           - os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
           - os: macos-14
             xcode: Xcode_16.2
     runs-on: ${{ matrix.os }}
diff --git a/.github/workflows/storage.yml b/.github/workflows/storage.yml
index 036037b5ca7..740b15c7766 100644
--- a/.github/workflows/storage.yml
+++ b/.github/workflows/storage.yml
@@ -88,7 +88,7 @@ jobs:
           #  xcode: Xcode_14.2 # TODO: the legacy ObjC quickstart doesn't build with Xcode 15.
           - swift: swift
             os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
     env:
       plist_secret: ${{ secrets.GHASecretsGPGPassphrase1 }}
       signin_secret: ${{ secrets.GHASecretsGPGPassphrase1 }}
@@ -153,7 +153,7 @@ jobs:
           - os: macos-14
             xcode: Xcode_16.2
           - os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     needs: pod_lib_lint
     steps:
diff --git a/.github/workflows/zip.yml b/.github/workflows/zip.yml
index 9879e942885..42a216c1567 100644
--- a/.github/workflows/zip.yml
+++ b/.github/workflows/zip.yml
@@ -114,9 +114,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
@@ -176,7 +174,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         include:
           - os: macos-15
-            xcode: Xcode_16.2
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v4
@@ -226,9 +224,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
@@ -277,9 +273,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
@@ -403,9 +397,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
@@ -427,6 +419,12 @@ jobs:
                                                "${HOME}"/ios_frameworks/Firebase/FirebaseFirestore/* \
                                                "${HOME}"/ios_frameworks/Firebase/FirebaseAuth/* \
                                                "${HOME}"/ios_frameworks/Firebase/FirebaseAnalytics/*
+    - name: Upload build logs on failure
+      if: ${{ failure() }}
+      uses: actions/upload-artifact@v4
+      with:
+        name: build_logs_firestore_${{ matrix.artifact }}_${{ matrix.build-env.os }}
+        path: sdk_zip/build_logs/
     - name: Xcode
       run: sudo xcode-select -s /Applications/${{ matrix.build-env.xcode }}.app/Contents/Developer
     - name: Install Secret GoogleService-Info.plist
@@ -487,9 +485,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
@@ -542,9 +538,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
@@ -597,9 +591,7 @@ jobs:
         artifact: [Firebase-actions-dir, Firebase-actions-dir-dynamic]
         build-env:
           - os: macos-15
-            xcode: Xcode_16.2
-          # - os: macos-15
-          #   xcode: Xcode_16.4
+            xcode: Xcode_16.4
     runs-on: ${{ matrix.build-env.os }}
     steps:
     - uses: actions/checkout@v4
diff --git a/scripts/build.sh b/scripts/build.sh
index 30b84004c3b..2be500a8bbc 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -187,8 +187,11 @@ tvos_flags=(
   -destination 'platform=tvOS Simulator,name=Apple TV'
 )
 visionos_flags=(
+  # As of Aug 15, 2025, the default OS "latest" was failing as it matched both
+  # the visionOS 26 beta and visionOS 2.5 (from Xcode 16.4) simulators;
+  # explicitly specifying OS=2.5 in destination as a workaround.
   -sdk 'xrsimulator'
-  -destination 'platform=visionOS Simulator,name=Apple Vision Pro'
+  -destination 'platform=visionOS Simulator,OS=2.5,name=Apple Vision Pro'
 )
 catalyst_flags=(
   ARCHS=x86_64 VALID_ARCHS=x86_64 SUPPORTS_MACCATALYST=YES -sdk macosx
@@ -489,12 +492,10 @@ case "$product-$platform-$method" in
       ../../../FirebaseRemoteConfig/Tests/Swift/AccessToken.json
 
     # Integration tests are only run on iOS to minimize flake failures.
-    # TODO(ncooke3): Remove -sdk and -destination flags and replace with "${xcb_flags[@]}"
     RunXcodebuild \
       -workspace 'gen/FirebaseRemoteConfig/FirebaseRemoteConfig.xcworkspace' \
       -scheme "FirebaseRemoteConfig-Unit-swift-api-tests" \
-      -sdk 'iphonesimulator' \
-      -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
+      "${xcb_flags[@]}" \
       build \
       test
     ;;
@@ -572,12 +573,10 @@ case "$product-$platform-$method" in
 
     if check_secrets; then
       # Integration tests are only run on iOS to minimize flake failures.
-      # TODO(ncooke3): Add back "${ios_flags[@]}". See #14657.
       RunXcodebuild \
         -workspace 'gen/FirebaseStorage/FirebaseStorage.xcworkspace' \
         -scheme "FirebaseStorage-Unit-integration" \
-        -sdk 'iphonesimulator' \
-        -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
+        "${ios_flags[@]}" \
         "${xcb_flags[@]}" \
         test
     fi
@@ -593,12 +592,10 @@ case "$product-$platform-$method" in
 
     if check_secrets; then
       # Integration tests are only run on iOS to minimize flake failures.
-      # TODO(ncooke3): Add back "${ios_flags[@]}". See #14657.
       RunXcodebuild \
         -workspace 'gen/FirebaseStorage/FirebaseStorage.xcworkspace' \
         -scheme "FirebaseStorage-Unit-ObjCIntegration" \
-        -sdk 'iphonesimulator' \
-        -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
+        "${ios_flags[@]}" \
         "${xcb_flags[@]}" \
         test
       fi
@@ -617,8 +614,8 @@ case "$product-$platform-$method" in
       RunXcodebuild \
         -workspace 'gen/FirebaseCombineSwift/FirebaseCombineSwift.xcworkspace' \
         -scheme "FirebaseCombineSwift-Unit-integration" \
-        -sdk 'iphonesimulator' \
-        -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
+        "${ios_flags[@]}" \
+        "${xcb_flags[@]}" \
         test
       fi
     ;;