diff --git a/.github/workflows/base_build.yaml b/.github/workflows/base_build.yaml
index 3ac7a9dae..3eed5a0a5 100644
--- a/.github/workflows/base_build.yaml
+++ b/.github/workflows/base_build.yaml
@@ -14,13 +14,13 @@ on:
 
 jobs:
   build:
-    runs-on: [macos-14]
+    runs-on: [macos-latest]
 
     steps:
       - name: Select Xcode
         uses: maxim-lobanov/setup-xcode@v1
         with:
-          xcode-version: 15.4.0
+          xcode-version: 16
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -31,7 +31,7 @@ jobs:
         uses: sersoft-gmbh/xcodebuild-action@v3
         with:
           action: build
-          build-settings: ONLY_ACTIVE_ARCH=NO TEST_AFTER_BUILD=NO
+          build-settings: ONLY_ACTIVE_ARCH=NO TEST_AFTER_BUILD=NO SWIFT_VERSION=5.9
           configuration: Debug
           derived-data-path: "${{ github.workspace }}/SplitApp"
           destination: ${{ inputs.destination }}
diff --git a/.github/workflows/base_ut.yaml b/.github/workflows/base_ut.yaml
index 8aedeaae8..b71660d8a 100644
--- a/.github/workflows/base_ut.yaml
+++ b/.github/workflows/base_ut.yaml
@@ -13,13 +13,13 @@ on:
 
 jobs:
   test:
-    runs-on: [macos-14]
+    runs-on: [macos-latest]
 
     steps:
       - name: Select Xcode
         uses: maxim-lobanov/setup-xcode@v1
         with:
-          xcode-version: 15.4.0
+          xcode-version: 16
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -30,7 +30,7 @@ jobs:
         uses: sersoft-gmbh/xcodebuild-action@v3
         with:
           action: test
-          build-settings: ONLY_ACTIVE_ARCH=NO
+          build-settings: ONLY_ACTIVE_ARCH=NO SWIFT_VERSION=5.9
           configuration: Debug
           derived-data-path: "${{github.workspace}}/SplitApp"
           destination: ${{ inputs.destination }}
diff --git a/.github/workflows/sonar.yml b/.github/workflows/sonar.yml
index 95a9fbc4f..716383bae 100644
--- a/.github/workflows/sonar.yml
+++ b/.github/workflows/sonar.yml
@@ -13,7 +13,7 @@ concurrency:
 jobs:
   build-and-collect-coverage:
     name: Build & Collect Coverage
-    runs-on: macos-15
+    runs-on: macos-latest
     timeout-minutes: 15
     steps:
       - name: Checkout
@@ -28,7 +28,7 @@ jobs:
             -project Split.xcodeproj \
             -scheme Split \
             -testPlan "SplitiOSFull" \
-            -destination 'platform=iOS Simulator,OS=18.4,name=iPhone 16' \
+            -destination 'platform=iOS Simulator,OS=18.4,name=iPhone 16 Pro Max' \
             -enableCodeCoverage YES \
             -resultBundlePath build/Logs/Test/TestResults.xcresult \
             -derivedDataPath build
diff --git a/.github/workflows/test_all.yaml b/.github/workflows/test_all.yaml
index 534026ada..012280dbd 100644
--- a/.github/workflows/test_all.yaml
+++ b/.github/workflows/test_all.yaml
@@ -36,4 +36,4 @@ jobs:
     uses: ./.github/workflows/base_ut.yaml
     with:
       test-plan: ${{ matrix.plan }}
-      destination: 'platform=iOS Simulator,OS=17.2,name=iPhone 15'
+      destination: 'platform=iOS Simulator,name=iPhone 16,OS=latest'
diff --git a/.github/workflows/xcframework.yaml b/.github/workflows/xcframework.yaml
index b8076747c..f2457100e 100644
--- a/.github/workflows/xcframework.yaml
+++ b/.github/workflows/xcframework.yaml
@@ -14,7 +14,7 @@ jobs:
     - name: Select Xcode
       uses: maxim-lobanov/setup-xcode@v1
       with:
-        xcode-version: 15.1.0
+        xcode-version: 16
 
     - uses: actions/checkout@v2
     - uses: actions/setup-python@v2
diff --git a/SplitTests/Fake/Network/TelemetryProducerStub.swift b/SplitTests/Fake/Network/TelemetryProducerStub.swift
index 1dae5d0a1..8689d01ab 100644
--- a/SplitTests/Fake/Network/TelemetryProducerStub.swift
+++ b/SplitTests/Fake/Network/TelemetryProducerStub.swift
@@ -28,6 +28,8 @@ class TelemetryStorageStub: TelemetryStorage {
     var impressions = [TelemetryImpressionsDataType: Int]()
     var events = [TelemetryEventsDataType: Int]()
 
+    var lock = NSLock()
+    
     var isFactoryDataRecorded = Atomic<Bool>(false)
 
     func recordLastSync(resource: Resource, time: Int64) {
@@ -148,6 +150,8 @@ class TelemetryStorageStub: TelemetryStorage {
     }
 
     func popTags() -> [String] {
+        lock.lock()
+        defer { lock.unlock() }
         popTagsCallCount+=1
         return []
     }
diff --git a/SplitTests/Fake/Storage/MySegmentsStorageStub.swift b/SplitTests/Fake/Storage/MySegmentsStorageStub.swift
index 072d466ba..7b5b403f9 100644
--- a/SplitTests/Fake/Storage/MySegmentsStorageStub.swift
+++ b/SplitTests/Fake/Storage/MySegmentsStorageStub.swift
@@ -20,6 +20,8 @@ class MySegmentsStorageStub: MySegmentsStorage {
     var getCountByKeyCalledCount = 0
     var getCountCalledCount = 0
     var changeNumber: Int64 = -1
+    
+    var lock = NSLock()
 
     var keys: Set<String> {
         return Set(segments.keys.map { $0 })
@@ -69,6 +71,8 @@ class MySegmentsStorageStub: MySegmentsStorage {
     }
 
     func getCount() -> Int {
+        lock.lock()
+        defer { lock.unlock() }
         getCountCalledCount+=1
         var count = 0
         for (_, value) in segments {
diff --git a/SplitTests/Service/Telemetry/TelemetryStatsRecorderWorkerTests.swift b/SplitTests/Service/Telemetry/TelemetryStatsRecorderWorkerTests.swift
index f3f9f5207..39dfea680 100644
--- a/SplitTests/Service/Telemetry/TelemetryStatsRecorderWorkerTests.swift
+++ b/SplitTests/Service/Telemetry/TelemetryStatsRecorderWorkerTests.swift
@@ -94,6 +94,7 @@ class TelemetryStatsRecorderWorkerTests: XCTestCase {
         statsRecorder.queue = DispatchQueue(label: "pepe")
         let queue = DispatchQueue(label: "concurrent-test", attributes: .concurrent)
         let group = DispatchGroup()
+        let expectation = self.expectation(description: "Concurrent flush finished")
 
         for _ in 0..<6 {
             group.enter()
@@ -110,6 +111,9 @@ class TelemetryStatsRecorderWorkerTests: XCTestCase {
             XCTAssertEqual(6, self.mySegmentsStorage.getCountCalledCount)
             XCTAssertEqual(6, self.myLargeSegmentsStorage.getCountCalledCount)
             XCTAssertEqual(6, self.telemetryStorage.popTagsCallCount)
+            expectation.fulfill()
         }
+        
+        waitForExpectations(timeout: 5)
     }
 }