From dfa279230c049d090bb48e41c38159d05d89af3f Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:26:12 +0300
Subject: [PATCH 01/23] Raise minimum iOS deployment target to 15.0

---
 OptableSDK.podspec                                   |  2 +-
 OptableSDK.xcodeproj/project.pbxproj                 | 12 ++++++------
 Package.swift                                        |  4 ++--
 .../demo-ios-objc.xcodeproj/project.pbxproj          |  4 ++--
 .../demo-ios-swift.xcodeproj/project.pbxproj         |  4 ++--
 5 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/OptableSDK.podspec b/OptableSDK.podspec
index 3c6f246..6584541 100644
--- a/OptableSDK.podspec
+++ b/OptableSDK.podspec
@@ -14,7 +14,7 @@ Pod::Spec.new do |spec|
   spec.author        = { "Optable Technologies Inc" => "support@optable.co" }
 
   spec.platform              = :ios
-  spec.ios.deployment_target = "12.0"
+  spec.ios.deployment_target = "15.0"
   spec.swift_version         = "5.0"
 
   spec.source        = { :git => "https://github.com/Optable/optable-ios-sdk.git", :tag => "#{spec.version}" }
diff --git a/OptableSDK.xcodeproj/project.pbxproj b/OptableSDK.xcodeproj/project.pbxproj
index 686c972..12615ab 100644
--- a/OptableSDK.xcodeproj/project.pbxproj
+++ b/OptableSDK.xcodeproj/project.pbxproj
@@ -286,7 +286,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
 				MTL_FAST_MATH = YES;
 				ONLY_ACTIVE_ARCH = YES;
@@ -347,7 +347,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
 				SDKROOT = iphoneos;
@@ -374,7 +374,7 @@
 				ENABLE_MODULE_VERIFIER = YES;
 				INFOPLIST_FILE = Source/Info.plist;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -407,7 +407,7 @@
 				ENABLE_MODULE_VERIFIER = YES;
 				INFOPLIST_FILE = Source/Info.plist;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -431,7 +431,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Tests/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -452,7 +452,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Tests/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
diff --git a/Package.swift b/Package.swift
index 9a158da..3fbbd15 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,11 +1,11 @@
-// swift-tools-version:5.3
+// swift-tools-version:5.5
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
 
 let package = Package(
     name: "OptableSDK",
-    platforms: [.iOS(.v12)],
+    platforms: [.iOS(.v15)],
     products: [
         // Products define the executables and libraries a package produces, and make them visible to other packages.
         .library(
diff --git a/demo-ios-objc/demo-ios-objc.xcodeproj/project.pbxproj b/demo-ios-objc/demo-ios-objc.xcodeproj/project.pbxproj
index 67e4701..3af9d3b 100644
--- a/demo-ios-objc/demo-ios-objc.xcodeproj/project.pbxproj
+++ b/demo-ios-objc/demo-ios-objc.xcodeproj/project.pbxproj
@@ -360,7 +360,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
 				MTL_FAST_MATH = YES;
 				ONLY_ACTIVE_ARCH = YES;
@@ -413,7 +413,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
 				SDKROOT = iphoneos;
diff --git a/demo-ios-swift/demo-ios-swift.xcodeproj/project.pbxproj b/demo-ios-swift/demo-ios-swift.xcodeproj/project.pbxproj
index cf29466..e5a10f0 100644
--- a/demo-ios-swift/demo-ios-swift.xcodeproj/project.pbxproj
+++ b/demo-ios-swift/demo-ios-swift.xcodeproj/project.pbxproj
@@ -348,7 +348,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
 				MTL_FAST_MATH = YES;
 				ONLY_ACTIVE_ARCH = YES;
@@ -402,7 +402,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
 				SDKROOT = iphoneos;

From eedee52a0658dad83333c415408a3e85742ac2ba Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:26:12 +0300
Subject: [PATCH 02/23] Fix deprecation warnings under iOS 15 target

---
 Source/Core/EdgeAPI.swift                 |  4 +++-
 Source/Misc/AppTrackingTransparency.swift | 25 ++++-------------------
 2 files changed, 7 insertions(+), 22 deletions(-)

diff --git a/Source/Core/EdgeAPI.swift b/Source/Core/EdgeAPI.swift
index 4d62e22..d3da536 100644
--- a/Source/Core/EdgeAPI.swift
+++ b/Source/Core/EdgeAPI.swift
@@ -148,7 +148,9 @@ extension EdgeAPI {
     private func resolveUserAgent(callback: @escaping (_ useragent: String) -> Void) {
         var wkUserAgent = ""
         let myGroup = DispatchGroup()
-        let window = UIApplication.shared.keyWindow
+        let window = UIApplication.shared.connectedScenes
+            .compactMap { ($0 as? UIWindowScene)?.keyWindow }
+            .first
         let webView = WKWebView(frame: UIScreen.main.bounds)
 
         webView.isHidden = true
diff --git a/Source/Misc/AppTrackingTransparency.swift b/Source/Misc/AppTrackingTransparency.swift
index 5139c9d..c9d18ac 100644
--- a/Source/Misc/AppTrackingTransparency.swift
+++ b/Source/Misc/AppTrackingTransparency.swift
@@ -29,21 +29,6 @@
             }
         #endif
 
-        // MARK: isAdvertisingTrackingEnabled
-
-        #if DEBUG
-            @available(iOS, introduced: 6, deprecated: 14,
-                       message: "Replaced by ATTrackingManager in AppTrackingTransparency.")
-            static var isAdvertisingTrackingEnabled_DebugOverride: Bool?
-            static var isAdvertisingTrackingEnabled: Bool {
-                isAdvertisingTrackingEnabled_DebugOverride ?? ASIdentifierManager.shared().isAdvertisingTrackingEnabled
-            }
-        #else
-            static var isAdvertisingTrackingEnabled: Bool {
-                ASIdentifierManager.shared().isAdvertisingTrackingEnabled
-            }
-        #endif
-
         // MARK: advertisingIdentifierAvailable
 
         #if DEBUG
@@ -57,14 +42,12 @@
                 }
             #endif
 
+            // The SDK requires iOS 15+, where AppTrackingTransparency is always available, so the
+            // pre-iOS 14 `ASIdentifierManager.isAdvertisingTrackingEnabled` fallback no longer applies.
             #if canImport(AppTrackingTransparency)
-                if #available(iOS 14, *) {
-                    return trackingStatus == .authorized
-                } else {
-                    return isAdvertisingTrackingEnabled
-                }
+                return trackingStatus == .authorized
             #else
-                return isAdvertisingTrackingEnabled
+                return false
             #endif
         }
 

From 21d10953b89ca61f889c80e0a136ad7b6d9ca827 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:26:12 +0300
Subject: [PATCH 03/23] Raise demo pod targets to iOS 15, update pods

---
 demo-ios-objc/Podfile       | 13 +++++++++++++
 demo-ios-objc/Podfile.lock  | 16 ++++++++--------
 demo-ios-swift/Podfile      | 13 +++++++++++++
 demo-ios-swift/Podfile.lock | 16 ++++++++--------
 4 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/demo-ios-objc/Podfile b/demo-ios-objc/Podfile
index db4bb9b..72b1e52 100644
--- a/demo-ios-objc/Podfile
+++ b/demo-ios-objc/Podfile
@@ -11,3 +11,16 @@ target 'demo-ios-objc' do
   pod 'PrebidMobile'
   
 end
+
+# Xcode 27 refuses to build targets whose deployment target is below iOS 15. Some third-party pods
+# (Google-Mobile-Ads-SDK, GoogleUserMessagingPlatform, PrebidMobile) still declare older minimums,
+# so raise them to the platform version declared above.
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    target.build_configurations.each do |config|
+      if config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'].to_f < 15.0
+        config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '15.0'
+      end
+    end
+  end
+end
diff --git a/demo-ios-objc/Podfile.lock b/demo-ios-objc/Podfile.lock
index 8e0556a..44d9e11 100644
--- a/demo-ios-objc/Podfile.lock
+++ b/demo-ios-objc/Podfile.lock
@@ -1,11 +1,11 @@
 PODS:
-  - Google-Mobile-Ads-SDK (13.7.0):
+  - Google-Mobile-Ads-SDK (13.11.0):
     - GoogleUserMessagingPlatform (>= 1.1)
   - GoogleUserMessagingPlatform (3.1.0)
   - OptableSDK (1.0.0)
-  - PrebidMobile (3.3.3):
-    - PrebidMobile/core (= 3.3.3)
-  - PrebidMobile/core (3.3.3)
+  - PrebidMobile (3.3.4):
+    - PrebidMobile/core (= 3.3.4)
+  - PrebidMobile/core (3.3.4)
 
 DEPENDENCIES:
   - Google-Mobile-Ads-SDK
@@ -23,11 +23,11 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  Google-Mobile-Ads-SDK: dd0ded6717d122c6a32c69dc4afcace7d276e4e4
+  Google-Mobile-Ads-SDK: 09d0868abe43b9f851b7b340a245679f0eafc96c
   GoogleUserMessagingPlatform: befe603da6501006420c206222acd449bba45a9c
-  OptableSDK: d7cb5f7a211f1bac2a0c25677f4c4b31ded8ed4e
-  PrebidMobile: 5ded0a10d6da41d4b140c1c8b86b42c7629133fa
+  OptableSDK: 127f749734ded99deff764f29bc1342b20153b2b
+  PrebidMobile: ce3afbb56904a5e8b3f5f5aa0696474d2786a96b
 
-PODFILE CHECKSUM: 84321d4bbdf19f72ce3dfa6f4cb2f0a9869574ad
+PODFILE CHECKSUM: 788f5abee95f41b7e281003e2cab30df58eb8547
 
 COCOAPODS: 1.16.2
diff --git a/demo-ios-swift/Podfile b/demo-ios-swift/Podfile
index 5e9d12e..7dfa9a5 100644
--- a/demo-ios-swift/Podfile
+++ b/demo-ios-swift/Podfile
@@ -11,3 +11,16 @@ target 'demo-ios-swift' do
   pod 'PrebidMobile'
 
 end
+
+# Xcode 27 refuses to build targets whose deployment target is below iOS 15. Some third-party pods
+# (Google-Mobile-Ads-SDK, GoogleUserMessagingPlatform, PrebidMobile) still declare older minimums,
+# so raise them to the platform version declared above.
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    target.build_configurations.each do |config|
+      if config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'].to_f < 15.0
+        config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '15.0'
+      end
+    end
+  end
+end
diff --git a/demo-ios-swift/Podfile.lock b/demo-ios-swift/Podfile.lock
index 59ae941..cd81e9f 100644
--- a/demo-ios-swift/Podfile.lock
+++ b/demo-ios-swift/Podfile.lock
@@ -1,11 +1,11 @@
 PODS:
-  - Google-Mobile-Ads-SDK (13.7.0):
+  - Google-Mobile-Ads-SDK (13.11.0):
     - GoogleUserMessagingPlatform (>= 1.1)
   - GoogleUserMessagingPlatform (3.1.0)
   - OptableSDK (1.0.0)
-  - PrebidMobile (3.3.3):
-    - PrebidMobile/core (= 3.3.3)
-  - PrebidMobile/core (3.3.3)
+  - PrebidMobile (3.3.4):
+    - PrebidMobile/core (= 3.3.4)
+  - PrebidMobile/core (3.3.4)
 
 DEPENDENCIES:
   - Google-Mobile-Ads-SDK
@@ -23,11 +23,11 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  Google-Mobile-Ads-SDK: dd0ded6717d122c6a32c69dc4afcace7d276e4e4
+  Google-Mobile-Ads-SDK: 09d0868abe43b9f851b7b340a245679f0eafc96c
   GoogleUserMessagingPlatform: befe603da6501006420c206222acd449bba45a9c
-  OptableSDK: d7cb5f7a211f1bac2a0c25677f4c4b31ded8ed4e
-  PrebidMobile: 5ded0a10d6da41d4b140c1c8b86b42c7629133fa
+  OptableSDK: 127f749734ded99deff764f29bc1342b20153b2b
+  PrebidMobile: ce3afbb56904a5e8b3f5f5aa0696474d2786a96b
 
-PODFILE CHECKSUM: aca8225c99e7af1a76b3862a46118652667f5944
+PODFILE CHECKSUM: ae16575987318eda44e4e135cd54cad3debe5193
 
 COCOAPODS: 1.16.2

From 92f42302b449d1a3f7b847e2b47d831c1ea23d17 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:26:12 +0300
Subject: [PATCH 04/23] Run CI on xcode-27 runner

---
 .github/workflows/ios-sdk-ci.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ios-sdk-ci.yml b/.github/workflows/ios-sdk-ci.yml
index 251beb7..6f0d999 100644
--- a/.github/workflows/ios-sdk-ci.yml
+++ b/.github/workflows/ios-sdk-ci.yml
@@ -10,7 +10,7 @@ on:
 jobs:
   sdk-tests:
     name: "SDK Tests"
-    runs-on: macos-15
+    runs-on: xcode-27
     steps:
       - name: Checkout Code
         uses: actions/checkout@v5
@@ -30,7 +30,7 @@ jobs:
 
   build-demo-swift:
     name: "Build Demo Swift"
-    runs-on: macos-15
+    runs-on: xcode-27
     needs: [sdk-tests]
     steps:
       - name: Checkout Code
@@ -58,7 +58,7 @@ jobs:
 
   build-demo-objc:
     name: "Build Demo Objective-C"
-    runs-on: macos-15
+    runs-on: xcode-27
     env:
       FL_OUTPUT_DIR: output
     needs: [sdk-tests]

From 84c0c12c45c6381a6752335906b0b95fdd06679b Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:26:12 +0300
Subject: [PATCH 05/23] Fix objc result check in Slack steps

---
 .github/workflows/ios-sdk-ci.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ios-sdk-ci.yml b/.github/workflows/ios-sdk-ci.yml
index 6f0d999..ceb2bdd 100644
--- a/.github/workflows/ios-sdk-ci.yml
+++ b/.github/workflows/ios-sdk-ci.yml
@@ -92,7 +92,7 @@ jobs:
     steps:
       - name: Successful Release Post to Slack
         uses: slackapi/slack-github-action@v2.1.1
-        if: ${{ github.event_name == 'push' && startsWith(github.ref, 'refs/tags/') && needs.build-demo-swift.result == 'success' && needs.build-demo-swift.result == 'success' }}
+        if: ${{ github.event_name == 'push' && startsWith(github.ref, 'refs/tags/') && needs.build-demo-swift.result == 'success' && needs.build-demo-objc.result == 'success' }}
         with:
           method: chat.postMessage
           token: "${{ secrets.SLACK_MESSENGER_APP_TOKEN }}"
@@ -117,7 +117,7 @@ jobs:
                     text: ":white_check_mark: *iOS SDK release:*\n${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
       - name: Build failure Post to Slack
         uses: slackapi/slack-github-action@v2.1.1
-        if: ${{ github.event_name == 'pull_request' && (needs.build-demo-swift.result != 'success' || needs.build-demo-swift.result != 'success')}}
+        if: ${{ github.event_name == 'pull_request' && (needs.build-demo-swift.result != 'success' || needs.build-demo-objc.result != 'success')}}
         with:
           method: chat.postMessage
           token: "${{ secrets.SLACK_MESSENGER_APP_TOKEN }}"

From 6648cfd19152f97a808e2e8d4f6d708d57e5c861 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:33:09 +0300
Subject: [PATCH 06/23] Clean up resundant comments

---
 Source/Misc/AppTrackingTransparency.swift | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Source/Misc/AppTrackingTransparency.swift b/Source/Misc/AppTrackingTransparency.swift
index c9d18ac..9d1bc87 100644
--- a/Source/Misc/AppTrackingTransparency.swift
+++ b/Source/Misc/AppTrackingTransparency.swift
@@ -42,8 +42,6 @@
                 }
             #endif
 
-            // The SDK requires iOS 15+, where AppTrackingTransparency is always available, so the
-            // pre-iOS 14 `ASIdentifierManager.isAdvertisingTrackingEnabled` fallback no longer applies.
             #if canImport(AppTrackingTransparency)
                 return trackingStatus == .authorized
             #else

From 0b4b4e176fb027ac57432dda4af7dddb3a3bf9e1 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Wed, 30 Sep 2026 20:48:24 +0300
Subject: [PATCH 07/23] Remove availability checks below iOS 15

---
 Source/Core/EdgeAPI.swift                     |  21 +---
 Source/Core/OptableIdentifierEncoder.swift    |  29 +----
 Source/Misc/AppTrackingTransparency.swift     | 119 +++++++-----------
 .../RangeReplaceableCollection+Compat.swift   |  22 ----
 Source/OptableSDK.swift                       |  19 +--
 Tests/Integration/OptableSDKTests.swift       |   4 -
 ...SDKHelpersIdentifiersEnrichmentTests.swift |   2 -
 7 files changed, 58 insertions(+), 158 deletions(-)
 delete mode 100644 Source/Misc/RangeReplaceableCollection+Compat.swift

diff --git a/Source/Core/EdgeAPI.swift b/Source/Core/EdgeAPI.swift
index d3da536..b0d5900 100644
--- a/Source/Core/EdgeAPI.swift
+++ b/Source/Core/EdgeAPI.swift
@@ -118,25 +118,8 @@ extension EdgeAPI {
                 completionHandler(data, response, error)
                 return
             }
-            if #available(iOS 13.0, *) {
-                if let passport = res.value(forHTTPHeaderField: self.kPassportHeader) {
-                    self.storage.setPassport(passport)
-                }
-            } else {
-                // In older versions of iOS, we have to resort searching through headers via res.allHeaderFields
-                // Unlike res.value(forHTTPHeaderField:...) which was introduced in iOS 13.0, allHeaderFields is
-                // case-sensitive, so we need to take special care to perform a case-INsensitive search:
-                for (key, value) in res.allHeaderFields {
-                    if let header = key as? String {
-                        let result: ComparisonResult = header.compare(self.kPassportHeader, options: NSString.CompareOptions.caseInsensitive)
-                        if result == .orderedSame {
-                            if let pp = value as? String {
-                                self.storage.setPassport(pp)
-                                break
-                            }
-                        }
-                    }
-                }
+            if let passport = res.value(forHTTPHeaderField: self.kPassportHeader) {
+                self.storage.setPassport(passport)
             }
             completionHandler(data, response, error)
         }
diff --git a/Source/Core/OptableIdentifierEncoder.swift b/Source/Core/OptableIdentifierEncoder.swift
index 0590761..8a65694 100644
--- a/Source/Core/OptableIdentifierEncoder.swift
+++ b/Source/Core/OptableIdentifierEncoder.swift
@@ -5,11 +5,8 @@
 //  Copyright © 2026 Optable Technologies, Inc. All rights reserved.
 //
 
-import CommonCrypto
+import CryptoKit
 import Foundation
-#if canImport(CryptoKit)
-    import CryptoKit
-#endif
 
 // MARK: - OptableIdentifierEncoder
 enum OptableIdentifierEncoder {
@@ -196,25 +193,9 @@ enum OptableIdentifierEncoder {
     }
 
     private static func sha256(data: Data) -> String {
-        #if canImport(CryptoKit)
-            if #available(iOS 13.0, *) {
-                return SHA256
-                    .hash(data: data)
-                    .compactMap({ String(format: "%02x", $0) })
-                    .joined()
-            }
-        #endif
-
-        return cchash(data)
-    }
-
-    private static func cchash(_ input: Data) -> String {
-        var digest = [UInt8](repeating: 0, count: Int(CC_SHA256_DIGEST_LENGTH))
-        input.withUnsafeBytes { bytes in
-            _ = CC_SHA256(bytes.baseAddress, CC_LONG(input.count), &digest)
-        }
-        return digest.makeIterator().compactMap {
-            String(format: "%02x", $0)
-        }.joined()
+        SHA256
+            .hash(data: data)
+            .compactMap({ String(format: "%02x", $0) })
+            .joined()
     }
 }
diff --git a/Source/Misc/AppTrackingTransparency.swift b/Source/Misc/AppTrackingTransparency.swift
index 9d1bc87..0410f5e 100644
--- a/Source/Misc/AppTrackingTransparency.swift
+++ b/Source/Misc/AppTrackingTransparency.swift
@@ -8,11 +8,7 @@
 #if canImport(AdSupport)
 
     import AdSupport
-
-    #if canImport(AppTrackingTransparency)
-        import AppTrackingTransparency
-    #endif
-
+    import AppTrackingTransparency
     import Foundation
 
     enum ATT {
@@ -42,11 +38,7 @@
                 }
             #endif
 
-            #if canImport(AppTrackingTransparency)
-                return trackingStatus == .authorized
-            #else
-                return false
-            #endif
+            return trackingStatus == .authorized
         }
 
         // MARK: attAvailable
@@ -62,86 +54,69 @@
                 }
             #endif
 
-            if #available(iOS 14, *) {
-                return true
-            } else {
-                return false
-            }
+            return true
         }
 
-        #if canImport(AppTrackingTransparency)
+        // MARK: canAuthorize
 
-            // MARK: canAuthorize
+        #if DEBUG
+            static var canAuthorize_DebugOverride: Bool?
+        #endif
 
+        static var canAuthorize: Bool {
             #if DEBUG
-                @available(iOS 14, *)
-                static var canAuthorize_DebugOverride: Bool?
+                if let override = canAuthorize_DebugOverride {
+                    return override
+                }
             #endif
 
-            static var canAuthorize: Bool {
-                if #available(iOS 14, *) {
-                    #if DEBUG
-                        if let override = canAuthorize_DebugOverride {
-                            return override
-                        }
-                    #endif
-
-                    return ATTrackingManager.trackingAuthorizationStatus == .notDetermined
-                } else {
-                    return false
-                }
-            }
+            return ATTrackingManager.trackingAuthorizationStatus == .notDetermined
+        }
+
+        // MARK: trackingStatus
 
-            // MARK: trackingStatus
+        #if DEBUG
+            static var trackingStatus_DebugOverride: ATTrackingManager.AuthorizationStatus?
+        #endif
 
+        static var trackingStatus: ATTrackingManager.AuthorizationStatus {
             #if DEBUG
-                @available(iOS 14, *)
-                static var trackingStatus_DebugOverride: ATTrackingManager.AuthorizationStatus?
+                return trackingStatus_DebugOverride ?? ATTrackingManager.trackingAuthorizationStatus
+            #else
+                return ATTrackingManager.trackingAuthorizationStatus
             #endif
+        }
 
-            @available(iOS 14, *)
-            static var trackingStatus: ATTrackingManager.AuthorizationStatus {
-                #if DEBUG
-                    return trackingStatus_DebugOverride ?? ATTrackingManager.trackingAuthorizationStatus
-                #else
-                    return ATTrackingManager.trackingAuthorizationStatus
-                #endif
-            }
+        // MARK: RequestAuthorization
 
-            // MARK: RequestAuthorization
-
-            @available(iOS 14, *)
-            static func requestATTAuthorization(completion: ((Bool) -> Void)? = nil) {
-                #if DEBUG
-                    if let override = trackingStatus_DebugOverride {
-                        completion?(override == .authorized)
-                        return
-                    }
-                #endif
-
-                ATTrackingManager.requestTrackingAuthorization { status in
-                    switch status {
-                    case .authorized:
-                        completion?(true)
-                    case .denied, .notDetermined, .restricted:
-                        completion?(false)
-                    @unknown default:
-                        completion?(true)
-                    }
+        static func requestATTAuthorization(completion: ((Bool) -> Void)? = nil) {
+            #if DEBUG
+                if let override = trackingStatus_DebugOverride {
+                    completion?(override == .authorized)
+                    return
                 }
-            }
+            #endif
 
-            @available(iOS 14, *)
-            @discardableResult
-            static func requestATTAuthorization() async -> Bool {
-                await withCheckedContinuation { continuation in
-                    requestATTAuthorization { isAuthorized in
-                        continuation.resume(returning: isAuthorized)
-                    }
+            ATTrackingManager.requestTrackingAuthorization { status in
+                switch status {
+                case .authorized:
+                    completion?(true)
+                case .denied, .notDetermined, .restricted:
+                    completion?(false)
+                @unknown default:
+                    completion?(true)
                 }
             }
+        }
 
-        #endif
+        @discardableResult
+        static func requestATTAuthorization() async -> Bool {
+            await withCheckedContinuation { continuation in
+                requestATTAuthorization { isAuthorized in
+                    continuation.resume(returning: isAuthorized)
+                }
+            }
+        }
     }
 
 #endif
diff --git a/Source/Misc/RangeReplaceableCollection+Compat.swift b/Source/Misc/RangeReplaceableCollection+Compat.swift
deleted file mode 100644
index 329a242..0000000
--- a/Source/Misc/RangeReplaceableCollection+Compat.swift
+++ /dev/null
@@ -1,22 +0,0 @@
-//
-//  RangeReplaceableCollection+Compat.swift
-//  OptableSDK
-//
-//  Copyright © 2026 Optable Technologies, Inc. All rights reserved.
-//
-
-import Foundation
-import SwiftUI
-
-extension RangeReplaceableCollection where Self: MutableCollection, Index == Int {
-    mutating func removeCompat(atOffsets offsets: IndexSet) {
-        if #available(iOS 13.0, *) {
-            remove(atOffsets: offsets)
-        } else {
-            // Remove from highest index to lowest to avoid shifting issues
-            for index in offsets.sorted(by: >) {
-                remove(at: index)
-            }
-        }
-    }
-}
diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index 308213f..23b315d 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -101,7 +101,6 @@ public extension OptableSDK {
 
      Instead of completion callbacks, results are returned via async/await.
      */
-    @available(iOS 13.0, *)
     func identify(_ ids: [OptableIdentifier]) async throws -> HTTPURLResponse {
         return try await withCheckedThrowingContinuation({ [unowned self] continuation in
             do {
@@ -164,7 +163,6 @@ public extension OptableSDK {
 
      Instead of completion callbacks, results are returned via async/await.
      */
-    @available(iOS 13.0, *)
     func targeting(_ ids: [OptableIdentifier]? = nil, hids: [OptableIdentifier]? = nil) async throws -> OptableTargeting {
         return try await withCheckedThrowingContinuation({ [unowned self] continuation in
             do {
@@ -197,7 +195,6 @@ public extension OptableSDK {
 
      Instead of completion callbacks, results are returned via async/await.
      */
-    @available(iOS 13.0, *)
     func witness(event: String, properties: [String: Any]) async throws -> HTTPURLResponse {
         return try await withCheckedThrowingContinuation({ [unowned self] continuation in
             do {
@@ -249,7 +246,6 @@ public extension OptableSDK {
 
      Instead of completion callbacks, results are returned via async/await.
      */
-    @available(iOS 13.0, *)
     func profile(traits: [String: Any], id: String? = nil, neighbors: [String]? = nil) async throws -> OptableTargeting {
         return try await withCheckedThrowingContinuation({ [unowned self] continuation in
             do {
@@ -432,18 +428,11 @@ extension OptableSDK {
            ATT.advertisingIdentifier != UUID(uuid: uuid_t(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) {
             let systemIDFA = ATT.advertisingIdentifier.uuidString
 
-            var idfaMatchingSystemIdxs: [Int] = []
-
-            for idx in ids.indices {
-                if case let .appleIDFA(value) = ids[idx] {
-                    if value == systemIDFA {
-                        idfaMatchingSystemIdxs.append(idx)
-                    }
-                }
-            }
-
             // Remove all matching systemIDFA (deduplicate)
-            ids.removeCompat(atOffsets: IndexSet(idfaMatchingSystemIdxs))
+            ids.removeAll { id in
+                if case let .appleIDFA(value) = id { return value == systemIDFA }
+                return false
+            }
 
             // Prepend all identifiers with systemIDFA
             ids.insert(.appleIDFA(systemIDFA), at: ids.startIndex)
diff --git a/Tests/Integration/OptableSDKTests.swift b/Tests/Integration/OptableSDKTests.swift
index 6dcb627..fbcfce5 100644
--- a/Tests/Integration/OptableSDKTests.swift
+++ b/Tests/Integration/OptableSDKTests.swift
@@ -24,7 +24,6 @@ class OptableSDKTests: XCTestCase {
     }
 
     // MARK: Identify
-    @available(iOS 13.0, *)
     func test_identify_async() async throws {
         let response = try await sdk.identify([.emailAddress("test@test.com")])
         XCTAssert(response.allHeaderFields.keys.contains("x-optable-visitor"))
@@ -52,7 +51,6 @@ class OptableSDKTests: XCTestCase {
     }
 
     // MARK: Target
-    @available(iOS 13.0, *)
     func test_target_async() async throws {
         let response = try await sdk.targeting([.emailAddress("test@test.com")])
         XCTAssert(response.targetingData.keys.isEmpty == false)
@@ -102,7 +100,6 @@ class OptableSDKTests: XCTestCase {
     }
 
     // MARK: Witness
-    @available(iOS 13.0, *)
     func test_witness_async() async throws {
         let response: HTTPURLResponse = try await sdk.witness(event: "test", properties: ["integration-test-witness": "integration-test-witness-value"])
         XCTAssert(response.allHeaderFields.keys.contains("x-optable-visitor"))
@@ -130,7 +127,6 @@ class OptableSDKTests: XCTestCase {
     }
 
     // MARK: Profile
-    @available(iOS 13.0, *)
     func test_profile_async() async throws {
         let response = try await sdk.profile(traits: ["integration-test-profile": "integration-test-profile-value"])
         XCTAssert(response.targetingData.keys.isEmpty == false)
diff --git a/Tests/Unit/OptableSDKHelpersIdentifiersEnrichmentTests.swift b/Tests/Unit/OptableSDKHelpersIdentifiersEnrichmentTests.swift
index 085cb4a..ea53d53 100644
--- a/Tests/Unit/OptableSDKHelpersIdentifiersEnrichmentTests.swift
+++ b/Tests/Unit/OptableSDKHelpersIdentifiersEnrichmentTests.swift
@@ -63,7 +63,6 @@ class OptableSDKHelpersIdentifiersEnrichmentTests: XCTestCase {
         }
     }
 
-    @available(iOS 14, *)
     func test_idfa_detection_enabled_enrich_system_idfa_same_as_user_idfa_prepend() {
         ATT.advertisingIdentifierAvailable_DebugOverride = true
         ATT.advertisingIdentifier_DebugOverride = UUID(uuidString: systemIDFA)
@@ -94,7 +93,6 @@ class OptableSDKHelpersIdentifiersEnrichmentTests: XCTestCase {
         }
     }
 
-    @available(iOS 14, *)
     func test_idfa_detection_enabled_enrich_system_idfa_user_idfa_persist() {
         ATT.advertisingIdentifierAvailable_DebugOverride = true
         ATT.advertisingIdentifier_DebugOverride = UUID(uuidString: systemIDFA)

From fa89ca153a2e3d971658b83ff2729e17232ad57f Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 09:57:13 +0300
Subject: [PATCH 08/23] Add Locked box and use it for ATT debug overrides

---
 Source/Misc/AppTrackingTransparency.swift | 35 +++++++++++++++++++----
 Source/Misc/Locked.swift                  | 28 ++++++++++++++++++
 2 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 Source/Misc/Locked.swift

diff --git a/Source/Misc/AppTrackingTransparency.swift b/Source/Misc/AppTrackingTransparency.swift
index 0410f5e..f87ffc6 100644
--- a/Source/Misc/AppTrackingTransparency.swift
+++ b/Source/Misc/AppTrackingTransparency.swift
@@ -11,11 +11,18 @@
     import AppTrackingTransparency
     import Foundation
 
+    /// The `*_DebugOverride` knobs are test-only hooks. Each one is backed by a `Locked` box, which keeps
+    /// the static accessors concurrency-safe under Swift 6 (plain `static var`s are rejected there).
     enum ATT {
         // MARK: advertisingIdentifier
 
         #if DEBUG
-            static var advertisingIdentifier_DebugOverride: UUID?
+            private static let _advertisingIdentifier_DebugOverride = Locked<UUID?>(nil)
+            static var advertisingIdentifier_DebugOverride: UUID? {
+                get { _advertisingIdentifier_DebugOverride.withLock { $0 } }
+                set { _advertisingIdentifier_DebugOverride.withLock { $0 = newValue } }
+            }
+
             static var advertisingIdentifier: UUID {
                 advertisingIdentifier_DebugOverride ?? ASIdentifierManager.shared().advertisingIdentifier
             }
@@ -28,7 +35,11 @@
         // MARK: advertisingIdentifierAvailable
 
         #if DEBUG
-            static var advertisingIdentifierAvailable_DebugOverride: Bool?
+            private static let _advertisingIdentifierAvailable_DebugOverride = Locked<Bool?>(nil)
+            static var advertisingIdentifierAvailable_DebugOverride: Bool? {
+                get { _advertisingIdentifierAvailable_DebugOverride.withLock { $0 } }
+                set { _advertisingIdentifierAvailable_DebugOverride.withLock { $0 = newValue } }
+            }
         #endif
 
         static var advertisingIdentifierAvailable: Bool {
@@ -44,7 +55,11 @@
         // MARK: attAvailable
 
         #if DEBUG
-            static var attAvailable_DebugOverride: Bool?
+            private static let _attAvailable_DebugOverride = Locked<Bool?>(nil)
+            static var attAvailable_DebugOverride: Bool? {
+                get { _attAvailable_DebugOverride.withLock { $0 } }
+                set { _attAvailable_DebugOverride.withLock { $0 = newValue } }
+            }
         #endif
 
         static var attAvailable: Bool {
@@ -60,7 +75,11 @@
         // MARK: canAuthorize
 
         #if DEBUG
-            static var canAuthorize_DebugOverride: Bool?
+            private static let _canAuthorize_DebugOverride = Locked<Bool?>(nil)
+            static var canAuthorize_DebugOverride: Bool? {
+                get { _canAuthorize_DebugOverride.withLock { $0 } }
+                set { _canAuthorize_DebugOverride.withLock { $0 = newValue } }
+            }
         #endif
 
         static var canAuthorize: Bool {
@@ -76,7 +95,11 @@
         // MARK: trackingStatus
 
         #if DEBUG
-            static var trackingStatus_DebugOverride: ATTrackingManager.AuthorizationStatus?
+            private static let _trackingStatus_DebugOverride = Locked<ATTrackingManager.AuthorizationStatus?>(nil)
+            static var trackingStatus_DebugOverride: ATTrackingManager.AuthorizationStatus? {
+                get { _trackingStatus_DebugOverride.withLock { $0 } }
+                set { _trackingStatus_DebugOverride.withLock { $0 = newValue } }
+            }
         #endif
 
         static var trackingStatus: ATTrackingManager.AuthorizationStatus {
@@ -89,7 +112,7 @@
 
         // MARK: RequestAuthorization
 
-        static func requestATTAuthorization(completion: ((Bool) -> Void)? = nil) {
+        static func requestATTAuthorization(completion: (@Sendable (Bool) -> Void)? = nil) {
             #if DEBUG
                 if let override = trackingStatus_DebugOverride {
                     completion?(override == .authorized)
diff --git a/Source/Misc/Locked.swift b/Source/Misc/Locked.swift
new file mode 100644
index 0000000..13c34e3
--- /dev/null
+++ b/Source/Misc/Locked.swift
@@ -0,0 +1,28 @@
+//
+//  Locked.swift
+//  OptableSDK
+//
+//  Copyright © 2026 Optable Technologies, Inc. All rights reserved.
+//
+
+import Foundation
+
+/// A value guarded by a lock, so it can be shared across threads under Swift 6 strict concurrency.
+/// Stands in for `Synchronization.Mutex` (iOS 18) and `OSAllocatedUnfairLock` (iOS 16).
+final class Locked<Value> {
+    private let lock = NSLock()
+    private var value: Value
+
+    init(_ value: Value) {
+        self.value = value
+    }
+
+    /// Runs `body` with exclusive access to the wrapped value and returns its result.
+    func withLock<T>(_ body: (inout Value) throws -> T) rethrows -> T {
+        lock.lock()
+        defer { lock.unlock() }
+        return try body(&value)
+    }
+}
+
+extension Locked: @unchecked Sendable where Value: Sendable {}

From 914a97b1ed0773cb61e225dedbc73f39a376bcd5 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 09:57:13 +0300
Subject: [PATCH 09/23] Resolve WebView user agent on the main actor

---
 Source/Core/EdgeAPI.swift | 43 ++++++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/Source/Core/EdgeAPI.swift b/Source/Core/EdgeAPI.swift
index b0d5900..9e3246b 100644
--- a/Source/Core/EdgeAPI.swift
+++ b/Source/Core/EdgeAPI.swift
@@ -22,19 +22,28 @@ final class EdgeAPI {
     var storage: LocalStorage
     var config: OptableConfig
 
-    var userAgent: String?
+    /// The `User-Agent` sent with every request: `config.customUserAgent` when set, otherwise the WebView's
+    /// user agent, resolved asynchronously on the main actor at init (nil until it arrives).
+    var userAgent: String? {
+        get { userAgentStore.withLock { $0 } }
+        set { userAgentStore.withLock { $0 = newValue } }
+    }
+
+    private let userAgentStore: Locked<String?>
 
     private lazy var jsonEncoder = JSONEncoder()
 
     init(_ config: OptableConfig) {
         self.config = config
         self.storage = LocalStorage(config)
+        self.userAgentStore = Locked(config.customUserAgent)
+
         if config.customUserAgent == nil {
-            self.resolveUserAgent { realUserAgent in
-                self.userAgent = realUserAgent
+            let userAgentStore = self.userAgentStore
+            Task { @MainActor in
+                let realUserAgent = await EdgeAPI.resolveWebViewUserAgent()
+                userAgentStore.withLock { $0 = realUserAgent }
             }
-        } else {
-            self.userAgent = config.customUserAgent
         }
     }
 
@@ -128,9 +137,10 @@ extension EdgeAPI {
 
 // MARK: - Private
 extension EdgeAPI {
-    private func resolveUserAgent(callback: @escaping (_ useragent: String) -> Void) {
-        var wkUserAgent = ""
-        let myGroup = DispatchGroup()
+    /// Reads `navigator.userAgent` from a hidden, throwaway WKWebView attached to the key window.
+    /// Returns an empty string when the WebView cannot provide one.
+    @MainActor
+    private static func resolveWebViewUserAgent() async -> String {
         let window = UIApplication.shared.connectedScenes
             .compactMap { ($0 as? UIWindowScene)?.keyWindow }
             .first
@@ -138,20 +148,15 @@ extension EdgeAPI {
 
         webView.isHidden = true
         window?.addSubview(webView)
-        myGroup.enter()
-
-        webView.loadHTMLString("<html></html>", baseURL: nil)
-        webView.evaluateJavaScript("navigator.userAgent", completionHandler: { (userAgent: Any?, error: Error?) in
-            if let userAgent = userAgent as? String {
-                wkUserAgent = userAgent
-            }
+        defer {
             webView.stopLoading()
             webView.removeFromSuperview()
-            myGroup.leave()
-        })
-        myGroup.notify(queue: .main) {
-            callback(wkUserAgent)
         }
+
+        webView.loadHTMLString("<html></html>", baseURL: nil)
+
+        let userAgent = try? await webView.evaluateJavaScript("navigator.userAgent")
+        return (userAgent as? String) ?? ""
     }
 
     func resolveHeaders() -> HTTPHeaders {

From 1088c1d24c2b286de8d50d6bfe92f874917c1b5e Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 09:57:13 +0300
Subject: [PATCH 10/23] Enable Swift 6 mode, mark OptableTargeting Sendable

---
 OptableSDK.xcodeproj/project.pbxproj | 4 ++--
 Source/Public/OptableTargeting.swift | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/OptableSDK.xcodeproj/project.pbxproj b/OptableSDK.xcodeproj/project.pbxproj
index 12615ab..b676310 100644
--- a/OptableSDK.xcodeproj/project.pbxproj
+++ b/OptableSDK.xcodeproj/project.pbxproj
@@ -388,7 +388,7 @@
 				SUPPORTS_MACCATALYST = NO;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -419,7 +419,7 @@
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;
 				SUPPORTS_MACCATALYST = NO;
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
diff --git a/Source/Public/OptableTargeting.swift b/Source/Public/OptableTargeting.swift
index f342c6c..e47ca1c 100644
--- a/Source/Public/OptableTargeting.swift
+++ b/Source/Public/OptableTargeting.swift
@@ -33,6 +33,11 @@ public class OptableTargeting: NSObject {
     }
 }
 
+// MARK: - Sendable
+/// Every stored property is a `let`, and the dictionaries only hold the immutable Foundation values
+/// produced by `JSONSerialization`, so instances can safely cross threads (e.g. resume a continuation).
+extension OptableTargeting: @unchecked Sendable {}
+
 // MARK: - Helpers
 
 extension OptableTargeting {

From df4dc824e4acbfe97a68ccabd9614ffc279f008c Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 10:50:45 +0300
Subject: [PATCH 11/23] Make completion handlers Sendable, lock-guard delegate
 and storage

---
 Source/Core/EdgeAPI.swift      | 18 +++++++++---------
 Source/Core/LocalStorage.swift | 11 +++++++----
 Source/OptableSDK.swift        | 28 +++++++++++++++++++---------
 3 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/Source/Core/EdgeAPI.swift b/Source/Core/EdgeAPI.swift
index 9e3246b..2f3a19b 100644
--- a/Source/Core/EdgeAPI.swift
+++ b/Source/Core/EdgeAPI.swift
@@ -17,10 +17,10 @@ import WebKit
 
  */
 final class EdgeAPI {
-    private let kPassportHeader: String = "X-Optable-Visitor"
+    private static let kPassportHeader: String = "X-Optable-Visitor"
 
-    var storage: LocalStorage
-    var config: OptableConfig
+    let storage: LocalStorage
+    let config: OptableConfig
 
     /// The `User-Agent` sent with every request: `config.customUserAgent` when set, otherwise the WebView's
     /// user agent, resolved asynchronously on the main actor at init (nil until it arrives).
@@ -31,7 +31,7 @@ final class EdgeAPI {
 
     private let userAgentStore: Locked<String?>
 
-    private lazy var jsonEncoder = JSONEncoder()
+    private let jsonEncoder = JSONEncoder()
 
     init(_ config: OptableConfig) {
         self.config = config
@@ -117,8 +117,8 @@ final class EdgeAPI {
 
 // MARK: - Dispatch
 extension EdgeAPI {
-    func dispatch(request: URLRequest, completionHandler: @escaping (Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask {
-        return URLSession.shared.dataTask(with: request) { data, response, error in
+    func dispatch(request: URLRequest, completionHandler: @escaping @Sendable (Data?, URLResponse?, Error?) -> Void) -> URLSessionDataTask {
+        return URLSession.shared.dataTask(with: request) { [storage] data, response, error in
             guard let res = response as? HTTPURLResponse, error == nil else {
                 completionHandler(data, response, error)
                 return
@@ -127,8 +127,8 @@ extension EdgeAPI {
                 completionHandler(data, response, error)
                 return
             }
-            if let passport = res.value(forHTTPHeaderField: self.kPassportHeader) {
-                self.storage.setPassport(passport)
+            if let passport = res.value(forHTTPHeaderField: Self.kPassportHeader) {
+                storage.setPassport(passport)
             }
             completionHandler(data, response, error)
         }
@@ -177,7 +177,7 @@ extension EdgeAPI {
         }
 
         if let passport: String = storage.getPassport() {
-            headers[kPassportHeader] = passport
+            headers[Self.kPassportHeader] = passport
         }
 
         return headers
diff --git a/Source/Core/LocalStorage.swift b/Source/Core/LocalStorage.swift
index 5ba0d73..81fe848 100644
--- a/Source/Core/LocalStorage.swift
+++ b/Source/Core/LocalStorage.swift
@@ -10,17 +10,20 @@ import Foundation
 
 /**
  The OptableSDK keeps some state in UserDefaults (https://developer.apple.com/documentation/foundation/userdefaults), a key/value store persisted across launches of the app. The state is therefore unique to the app+device, and not globally unique to the app across devices.
+
+ `@unchecked Sendable`: `UserDefaults` is thread-safe, targeting reads and writes are serialized by `lock`,
+ and the remaining state is immutable (`config` is only read).
  */
-final class LocalStorage: NSObject {
+final class LocalStorage: NSObject, @unchecked Sendable {
     private let targetingDataKey: String
     private let gamTargetingKeywordsKey: String
     private let ortb2Key: String
     private let id5SignatureKey: String
 
     let keyPfx: String = "OPTABLE"
-    var passportKey: String
-    var targetingKey: String
-    var targetingStoredAtKey: String
+    let passportKey: String
+    let targetingKey: String
+    let targetingStoredAtKey: String
     
     private let config: OptableConfig
     
diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index 23b315d..e2627cd 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -47,7 +47,12 @@ public protocol OptableDelegate {
 @objc
 public class OptableSDK: NSObject {
     @objc
-    public var delegate: OptableDelegate?
+    public var delegate: OptableDelegate? {
+        get { delegateStore.withLock { $0 } }
+        set { delegateStore.withLock { $0 = newValue } }
+    }
+
+    private let delegateStore = Locked<OptableDelegate?>(nil)
 
     let config: OptableConfig
     let api: EdgeAPI
@@ -72,6 +77,11 @@ public class OptableSDK: NSObject {
     }
 }
 
+// MARK: - Sendable
+/// `@unchecked`: `delegate` is lock-guarded, `api` holds no mutable state beyond its lock-guarded user agent,
+/// and `config` is the integrator's object, which the SDK only reads.
+extension OptableSDK: @unchecked Sendable {}
+
 // MARK: - Identify
 public extension OptableSDK {
     /**
@@ -91,7 +101,7 @@ public extension OptableSDK {
      }
      ```
      */
-    func identify(_ ids: [OptableIdentifier], completion: @escaping (Result<HTTPURLResponse, Error>) -> Void) throws {
+    func identify(_ ids: [OptableIdentifier], completion: @escaping @Sendable (Result<HTTPURLResponse, Error>) -> Void) throws {
         try _identify(ids, completion: completion)
     }
 
@@ -137,7 +147,7 @@ public extension OptableSDK {
      On success, the result is cached in client storage. You can read it using targetingFromCache()
      and clear it using targetingClearCache().
      */
-    func targeting(_ ids: [OptableIdentifier]? = nil, hids: [OptableIdentifier]? = nil, completion: @escaping (Result<OptableTargeting, Error>) -> Void) throws {
+    func targeting(_ ids: [OptableIdentifier]? = nil, hids: [OptableIdentifier]? = nil, completion: @escaping @Sendable (Result<OptableTargeting, Error>) -> Void) throws {
         try _targeting(ids: ids, hids: hids, completion: completion)
     }
 
@@ -185,7 +195,7 @@ public extension OptableSDK {
      - .success(HTTPURLResponse) on success
      - .failure(Error) on failure
      */
-    func witness(event: String, properties: [String: Any], _ completion: @escaping (Result<HTTPURLResponse, Error>) -> Void) throws {
+    func witness(event: String, properties: [String: Any], _ completion: @escaping @Sendable (Result<HTTPURLResponse, Error>) -> Void) throws {
         try _witness(event: event, properties: properties, completion: completion)
     }
 
@@ -236,7 +246,7 @@ public extension OptableSDK {
 
      The resulting OptableTargeting is also cached for targetingFromCache().
      */
-    func profile(traits: [String: Any], id: String? = nil, neighbors: [String]? = nil, _ completion: @escaping (Result<OptableTargeting, Error>) -> Void) throws {
+    func profile(traits: [String: Any], id: String? = nil, neighbors: [String]? = nil, _ completion: @escaping @Sendable (Result<OptableTargeting, Error>) -> Void) throws {
         try _profile(traits: traits, id: id, neighbors: neighbors, completion: completion)
     }
 
@@ -298,7 +308,7 @@ public extension OptableSDK {
 
 // MARK: - Internal
 extension OptableSDK {
-    func _identify(_ ids: [OptableIdentifier], completion: @escaping (Result<HTTPURLResponse, Error>) -> Void) throws {
+    func _identify(_ ids: [OptableIdentifier], completion: @escaping @Sendable (Result<HTTPURLResponse, Error>) -> Void) throws {
         var ids = ids
 
         enrichIfNeeded(ids: &ids)
@@ -325,7 +335,7 @@ extension OptableSDK {
         }).resume()
     }
 
-    func _targeting(ids: [OptableIdentifier]?, hids: [OptableIdentifier]?, completion: @escaping (Result<OptableTargeting, Error>) -> Void) throws {
+    func _targeting(ids: [OptableIdentifier]?, hids: [OptableIdentifier]?, completion: @escaping @Sendable (Result<OptableTargeting, Error>) -> Void) throws {
         var ids = ids ?? []
         var hids = hids ?? []
 
@@ -365,7 +375,7 @@ extension OptableSDK {
         }).resume()
     }
 
-    func _witness(event: String, properties: [String: Any], completion: @escaping (Result<HTTPURLResponse, Error>) -> Void) throws {
+    func _witness(event: String, properties: [String: Any], completion: @escaping @Sendable (Result<HTTPURLResponse, Error>) -> Void) throws {
         guard let request = try api.witness(event: event, properties: properties) else {
             throw OptableError.witness("Failed to create witness request")
         }
@@ -388,7 +398,7 @@ extension OptableSDK {
         }).resume()
     }
 
-    func _profile(traits: [String: Any], id: String?, neighbors: [String]?, completion: @escaping (Result<OptableTargeting, Error>) -> Void) throws {
+    func _profile(traits: [String: Any], id: String?, neighbors: [String]?, completion: @escaping @Sendable (Result<OptableTargeting, Error>) -> Void) throws {
         guard let request = try api.profile(traits: traits, id: id, neighbors: neighbors) else {
             throw OptableError.profile("Failed to create profile request")
         }

From 1b090ffd1857a54834e8b3775d87677c5500ed13 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 11:01:12 +0300
Subject: [PATCH 12/23] Make LocalStorage checked Sendable, pass cacheTTL into
 getTargeting

---
 Source/Core/LocalStorage.swift          | 24 +++++----
 Source/OptableSDK.swift                 |  2 +-
 Tests/Integration/OptableSDKTests.swift | 17 +++++++
 Tests/Unit/LocalStorageTests.swift      | 66 +++++++++++--------------
 4 files changed, 58 insertions(+), 51 deletions(-)

diff --git a/Source/Core/LocalStorage.swift b/Source/Core/LocalStorage.swift
index 81fe848..7f719f2 100644
--- a/Source/Core/LocalStorage.swift
+++ b/Source/Core/LocalStorage.swift
@@ -11,10 +11,10 @@ import Foundation
 /**
  The OptableSDK keeps some state in UserDefaults (https://developer.apple.com/documentation/foundation/userdefaults), a key/value store persisted across launches of the app. The state is therefore unique to the app+device, and not globally unique to the app across devices.
 
- `@unchecked Sendable`: `UserDefaults` is thread-safe, targeting reads and writes are serialized by `lock`,
- and the remaining state is immutable (`config` is only read).
+ `Sendable`: every stored property is immutable, `UserDefaults` is thread-safe, and targeting reads and writes
+ are serialized by `lock`.
  */
-final class LocalStorage: NSObject, @unchecked Sendable {
+final class LocalStorage: NSObject, Sendable {
     private let targetingDataKey: String
     private let gamTargetingKeywordsKey: String
     private let ortb2Key: String
@@ -24,9 +24,7 @@ final class LocalStorage: NSObject, @unchecked Sendable {
     let passportKey: String
     let targetingKey: String
     let targetingStoredAtKey: String
-    
-    private let config: OptableConfig
-    
+
     private let lock = NSLock()
 
     init(_ config: OptableConfig) {
@@ -36,8 +34,6 @@ final class LocalStorage: NSObject, @unchecked Sendable {
             .data(using: .utf8)?
             .base64EncodedString()
 
-        self.config = config
-
         self.passportKey = self.keyPfx + "_PASS_" + (base64Key ?? "UNKNOWN")
         self.targetingKey = self.keyPfx + "_TGT_" + (base64Key ?? "UNKNOWN")
 
@@ -56,13 +52,15 @@ final class LocalStorage: NSObject, @unchecked Sendable {
         UserDefaults.standard.set(passport, forKey: passportKey)
     }
 
-    func getTargeting() -> OptableTargeting? {
+    /// Returns the stored targeting entry while it is younger than `cacheTTL`. An expired entry is removed
+    /// from storage and reported as absent.
+    func getTargeting(cacheTTL: TimeInterval) -> OptableTargeting? {
         lock.synchronized {
             guard let targetingData = UserDefaults.standard.object(forKey: targetingDataKey) as? [String: Any] else {
                 return nil
             }
 
-            guard isTargetingFresh() else {
+            guard isTargetingFresh(cacheTTL: cacheTTL) else {
                 removeTargetingEntry()
                 return nil
             }
@@ -108,8 +106,8 @@ final class LocalStorage: NSObject, @unchecked Sendable {
         UserDefaults.standard.removeObject(forKey: targetingStoredAtKey)
     }
 
-    /// Whether the stored targeting entry was fetched recently enough to still be served, per `config.cacheTTL`. The caller must hold `lock`.
-    private func isTargetingFresh() -> Bool {
+    /// Whether the stored targeting entry was fetched recently enough to still be served, per `cacheTTL`. The caller must hold `lock`.
+    private func isTargetingFresh(cacheTTL: TimeInterval) -> Bool {
         // NOTE: A missing timestamp means the entry predates cache expiry support, so its age is unknowable - treat it as expired.
         guard let storedAt = UserDefaults.standard.object(forKey: targetingStoredAtKey) as? TimeInterval else {
             return false
@@ -117,6 +115,6 @@ final class LocalStorage: NSObject, @unchecked Sendable {
         
         let age = Date().timeIntervalSince1970 - storedAt
         
-        return age >= 0 && age < config.cacheTTL
+        return age >= 0 && age < cacheTTL
     }
 }
diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index e2627cd..de1a907 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -156,7 +156,7 @@ public extension OptableSDK {
     /// reported as absent and is cleared from storage.
     @objc
     func targetingFromCache() -> OptableTargeting? {
-        return self.api.storage.getTargeting()
+        return self.api.storage.getTargeting(cacheTTL: config.cacheTTL)
     }
 
     /// targetingClearCache() clears any previously cached targeting data.
diff --git a/Tests/Integration/OptableSDKTests.swift b/Tests/Integration/OptableSDKTests.swift
index fbcfce5..f54a184 100644
--- a/Tests/Integration/OptableSDKTests.swift
+++ b/Tests/Integration/OptableSDKTests.swift
@@ -99,6 +99,23 @@ class OptableSDKTests: XCTestCase {
         XCTAssertNil(sdk.targetingFromCache())
     }
 
+    func test_targetingFromCache_usesCurrentConfigCacheTTL() {
+        let config = OptableConfig(tenant: T.api.tenant.prebidtest, originSlug: T.api.slug.iosSDK, cacheTTL: 60)
+        let sdk = OptableSDK(config: config)
+
+        // Seed storage with an entry that is 90 seconds old
+        sdk.api.storage.setTargeting(OptableTargeting(optableTargeting: ["foo": "bar"]))
+        UserDefaults.standard.setValue(Date().timeIntervalSince1970 - 90, forKey: sdk.api.storage.targetingStoredAtKey)
+
+        // Raising the TTL after init keeps the entry readable
+        config.cacheTTL = 120
+        XCTAssertNotNil(sdk.targetingFromCache())
+
+        // Lowering it below the entry's age expires it
+        config.cacheTTL = 60
+        XCTAssertNil(sdk.targetingFromCache())
+    }
+
     // MARK: Witness
     func test_witness_async() async throws {
         let response: HTTPURLResponse = try await sdk.witness(event: "test", properties: ["integration-test-witness": "integration-test-witness-value"])
diff --git a/Tests/Unit/LocalStorageTests.swift b/Tests/Unit/LocalStorageTests.swift
index 9f87e1d..61c8215 100644
--- a/Tests/Unit/LocalStorageTests.swift
+++ b/Tests/Unit/LocalStorageTests.swift
@@ -29,7 +29,7 @@ class LocalStorageTests: XCTestCase {
         
         localStorage.setTargeting(optableTargetingFull)
         
-        let readTargeting = localStorage.getTargeting()
+        let readTargeting = localStorage.getTargeting(cacheTTL: OptableConfig.defaultCacheTTL)
         XCTAssert(readTargeting != nil)
         XCTAssert(readTargeting!.targetingData as NSDictionary == kOptableTargeting)
         XCTAssert(readTargeting!.gamTargetingKeywords as? NSDictionary == kGamTargetingKeywords)
@@ -45,7 +45,7 @@ class LocalStorageTests: XCTestCase {
         
         localStorage.setTargeting(optableTargetingFull)
         
-        let readTargeting = localStorage.getTargeting()
+        let readTargeting = localStorage.getTargeting(cacheTTL: OptableConfig.defaultCacheTTL)
         XCTAssert(readTargeting != nil)
         XCTAssert(readTargeting!.targetingData as NSDictionary == kOptableTargeting)
         XCTAssert(readTargeting!.gamTargetingKeywords as? NSDictionary == nil)
@@ -61,7 +61,7 @@ class LocalStorageTests: XCTestCase {
         
         localStorage.setTargeting(optableTargetingFull)
         
-        let readTargeting = localStorage.getTargeting()
+        let readTargeting = localStorage.getTargeting(cacheTTL: OptableConfig.defaultCacheTTL)
         XCTAssert(readTargeting != nil)
         XCTAssert(readTargeting!.targetingData as NSDictionary == kOptableTargeting)
         XCTAssert(readTargeting!.gamTargetingKeywords as? NSDictionary == kGamTargetingKeywords)
@@ -95,94 +95,94 @@ class LocalStorageTests: XCTestCase {
         
         localStorage.clearTargeting()
         
-        XCTAssert(localStorage.getTargeting() == nil)
+        XCTAssert(localStorage.getTargeting(cacheTTL: OptableConfig.defaultCacheTTL) == nil)
     }
     
     // MARK: - Cache TTL
     func testTargetingIsReturnedWithinTTL() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 30)
 
-        XCTAssertNotNil(storage.getTargeting())
+        XCTAssertNotNil(storage.getTargeting(cacheTTL: 60))
     }
 
     func testTargetingIsNilPastTTL() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 61)
 
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 60))
     }
 
     func testTargetingExpiresAtExactlyTTL() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 60)
 
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 60))
     }
 
     func testZeroTTLDisablesCaching() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 0)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 0)
 
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 0))
     }
 
     func testExpiredTargetingIsClearedFromStorage() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 61)
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 60))
 
         setStoredAge(storage, to: 0)
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 60))
     }
 
     func testTargetingWithoutStoredTimestampIsTreatedAsExpired() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
 
         UserDefaults.standard.removeObject(forKey: storage.targetingStoredAtKey)
 
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 60))
     }
 
     func testTargetingIsNilWhenStoredInTheFuture() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: -30)
 
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: 60))
     }
 
     func testDefaultTTLKeepsTargetingFreshJustUnderTwentyFourHours() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: nil)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 24 * 60 * 60 - 60)
 
-        XCTAssertNotNil(storage.getTargeting())
+        XCTAssertNotNil(storage.getTargeting(cacheTTL: OptableConfig.defaultCacheTTL))
     }
 
     func testDefaultTTLExpiresTargetingPastTwentyFourHours() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: nil)
+        let storage = makeStorageWithStoredTargeting()
 
         setStoredAge(storage, to: 24 * 60 * 60 + 60)
 
-        XCTAssertNil(storage.getTargeting())
+        XCTAssertNil(storage.getTargeting(cacheTTL: OptableConfig.defaultCacheTTL))
     }
 
     // MARK: - Thread safety
     /**
      A stale read must never wipe an entry that was stored concurrently.
 
-     Without mutual exclusion, `getTargeting()` can judge the old entry expired, then lose the CPU to a
+     Without mutual exclusion, `getTargeting(cacheTTL:)` can judge the old entry expired, then lose the CPU to a
      `setTargeting(_:)` that stores a fresh one, then resume and clear it. Whichever order the two calls
      serialize in, a fresh entry must be readable afterwards.
      */
     func testConcurrentReadOfExpiredEntryDoesNotWipeFreshWrite() {
-        let storage = makeStorageWithStoredTargeting(cacheTTL: 60)
+        let storage = makeStorageWithStoredTargeting()
         let freshTargeting = OptableTargeting(
             optableTargeting: kOptableTargeting as! [String: Any],
             gamTargetingKeywords: kGamTargetingKeywords as? [String: Any],
@@ -195,12 +195,12 @@ class LocalStorageTests: XCTestCase {
 
             let group = DispatchGroup()
             let queue = DispatchQueue.global(qos: .userInitiated)
-            queue.async(group: group) { _ = storage.getTargeting() }
+            queue.async(group: group) { _ = storage.getTargeting(cacheTTL: 60) }
             queue.async(group: group) { storage.setTargeting(freshTargeting) }
             group.wait()
 
-            XCTAssertNotNil(storage.getTargeting(), "fresh entry was wiped by a concurrent stale read on iteration \(iteration)")
-            if storage.getTargeting() == nil { break }
+            XCTAssertNotNil(storage.getTargeting(cacheTTL: 60), "fresh entry was wiped by a concurrent stale read on iteration \(iteration)")
+            if storage.getTargeting(cacheTTL: 60) == nil { break }
         }
     }
 
@@ -209,17 +209,9 @@ class LocalStorageTests: XCTestCase {
      Builds a LocalStorage with targeting already stored in it.
 
      Each call uses a unique tenant so that tests never share UserDefaults keys.
-     Passing a nil `cacheTTL` leaves the config default in place.
      */
-    private func makeStorageWithStoredTargeting(
-        cacheTTL: TimeInterval?,
-        function: String = #function
-    ) -> LocalStorage {
+    private func makeStorageWithStoredTargeting(function: String = #function) -> LocalStorage {
         let config = OptableConfig(tenant: "tenant-\(function)", originSlug: "slug")
-        if let cacheTTL {
-            config.cacheTTL = cacheTTL
-        }
-
         let storage = LocalStorage(config)
         storage.setTargeting(
             OptableTargeting(

From 7c46c57dc1164cd3ff0f6d591427f45f6b1397f1 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 11:29:14 +0300
Subject: [PATCH 13/23] Declare Swift 6 in Package.swift and podspec

---
 OptableSDK.podspec          | 2 +-
 Package.swift               | 5 +++--
 demo-ios-objc/Podfile.lock  | 2 +-
 demo-ios-swift/Podfile.lock | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/OptableSDK.podspec b/OptableSDK.podspec
index 6584541..f695841 100644
--- a/OptableSDK.podspec
+++ b/OptableSDK.podspec
@@ -15,7 +15,7 @@ Pod::Spec.new do |spec|
 
   spec.platform              = :ios
   spec.ios.deployment_target = "15.0"
-  spec.swift_version         = "5.0"
+  spec.swift_version         = "6.0"
 
   spec.source        = { :git => "https://github.com/Optable/optable-ios-sdk.git", :tag => "#{spec.version}" }
   spec.source_files  = "Source/**/*.{h,m,swift}"
diff --git a/Package.swift b/Package.swift
index 3fbbd15..e0f16d0 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.5
+// swift-tools-version:6.0
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
@@ -28,5 +28,6 @@ let package = Package(
             name: "OptableSDKTests",
             dependencies: ["OptableSDK"],
             path: "Tests"),
-    ]
+    ],
+    swiftLanguageModes: [.v6]
 )
diff --git a/demo-ios-objc/Podfile.lock b/demo-ios-objc/Podfile.lock
index 44d9e11..2e99555 100644
--- a/demo-ios-objc/Podfile.lock
+++ b/demo-ios-objc/Podfile.lock
@@ -25,7 +25,7 @@ EXTERNAL SOURCES:
 SPEC CHECKSUMS:
   Google-Mobile-Ads-SDK: 09d0868abe43b9f851b7b340a245679f0eafc96c
   GoogleUserMessagingPlatform: befe603da6501006420c206222acd449bba45a9c
-  OptableSDK: 127f749734ded99deff764f29bc1342b20153b2b
+  OptableSDK: d96e3936148f2e1c305573b628efc8299e47c097
   PrebidMobile: ce3afbb56904a5e8b3f5f5aa0696474d2786a96b
 
 PODFILE CHECKSUM: 788f5abee95f41b7e281003e2cab30df58eb8547
diff --git a/demo-ios-swift/Podfile.lock b/demo-ios-swift/Podfile.lock
index cd81e9f..56c0d8d 100644
--- a/demo-ios-swift/Podfile.lock
+++ b/demo-ios-swift/Podfile.lock
@@ -25,7 +25,7 @@ EXTERNAL SOURCES:
 SPEC CHECKSUMS:
   Google-Mobile-Ads-SDK: 09d0868abe43b9f851b7b340a245679f0eafc96c
   GoogleUserMessagingPlatform: befe603da6501006420c206222acd449bba45a9c
-  OptableSDK: 127f749734ded99deff764f29bc1342b20153b2b
+  OptableSDK: d96e3936148f2e1c305573b628efc8299e47c097
   PrebidMobile: ce3afbb56904a5e8b3f5f5aa0696474d2786a96b
 
 PODFILE CHECKSUM: ae16575987318eda44e4e135cd54cad3debe5193

From b76da88b5cd8ed853f079c7390206a2d829b9cf7 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 11:31:10 +0300
Subject: [PATCH 14/23] Mark OptableIdentifier Sendable

---
 Source/Public/OptableIdentifier.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Source/Public/OptableIdentifier.swift b/Source/Public/OptableIdentifier.swift
index 4bc5e51..2748120 100644
--- a/Source/Public/OptableIdentifier.swift
+++ b/Source/Public/OptableIdentifier.swift
@@ -15,7 +15,7 @@ import Foundation
  [](https://docs.optable.co/optable-documentation/getting-started/reference/identifier-types)
 
  */
-public enum OptableIdentifier {
+public enum OptableIdentifier: Sendable {
     // Personal identifiers,
     case emailAddress(String) // e
     case phoneNumber(String) // p

From 0d62ac4afaa408fc5c805d103a54934ead506dac Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 11:37:59 +0300
Subject: [PATCH 15/23] Build the test target in Swift 6 mode

---
 OptableSDK.xcodeproj/project.pbxproj | 4 ++--
 Tests/Unit/LocalStorageTests.swift   | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/OptableSDK.xcodeproj/project.pbxproj b/OptableSDK.xcodeproj/project.pbxproj
index b676310..2937569 100644
--- a/OptableSDK.xcodeproj/project.pbxproj
+++ b/OptableSDK.xcodeproj/project.pbxproj
@@ -440,7 +440,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = co.optable.OptableSDKTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -461,7 +461,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = co.optable.OptableSDKTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
diff --git a/Tests/Unit/LocalStorageTests.swift b/Tests/Unit/LocalStorageTests.swift
index 61c8215..0176710 100644
--- a/Tests/Unit/LocalStorageTests.swift
+++ b/Tests/Unit/LocalStorageTests.swift
@@ -237,7 +237,7 @@ class LocalStorageTests: XCTestCase {
     }
 }
 
-private let kOptableTargeting: NSDictionary = [
+private var kOptableTargeting: NSDictionary { [
     "user": [
     ],
     "resolved_ids": [
@@ -357,10 +357,10 @@ private let kOptableTargeting: NSDictionary = [
             ],
         ],
     ],
-]
+] }
 
-private let kGamTargetingKeywords: NSDictionary = [
+private var kGamTargetingKeywords: NSDictionary { [
     "optable-test": "082793f9",
-]
+] }
 
 private let kORTB2: String = "ortb2_data"

From 2fb8b853cf7fd894919e9e9a1cba3bdcfaee87c9 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 12:16:20 +0300
Subject: [PATCH 16/23] Make OptableConfig thread-safe and Sendable

---
 Source/OptableSDK.swift           |   3 +-
 Source/Public/OptableConfig.swift | 107 ++++++++++++++++++++++++------
 2 files changed, 89 insertions(+), 21 deletions(-)

diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index de1a907..b3aa88f 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -79,7 +79,8 @@ public class OptableSDK: NSObject {
 
 // MARK: - Sendable
 /// `@unchecked`: `delegate` is lock-guarded, `api` holds no mutable state beyond its lock-guarded user agent,
-/// and `config` is the integrator's object, which the SDK only reads.
+/// and `config` is `Sendable`. Unchecked only because `OptableDelegate` is an `@objc` protocol whose conformers
+/// cannot be required to be `Sendable`.
 extension OptableSDK: @unchecked Sendable {}
 
 // MARK: - Identify
diff --git a/Source/Public/OptableConfig.swift b/Source/Public/OptableConfig.swift
index 65b829e..9585bc8 100644
--- a/Source/Public/OptableConfig.swift
+++ b/Source/Public/OptableConfig.swift
@@ -8,8 +8,14 @@
 
 import Foundation
 
+/**
+ The configuration of an `OptableSDK` instance.
+
+ Every property is backed by its own lock, so the integrator may read and write it from any thread while the SDK
+ reads it.
+ */
 @objc
-public class OptableConfig: NSObject {
+public final class OptableConfig: NSObject, Sendable {
     // MARK: Constants
     /// The default lifetime of cached targeting data: 24 hours.
     @objc
@@ -18,42 +24,78 @@ public class OptableConfig: NSObject {
     // MARK: Required
     /// The tenant name associated with the configuration. E.g. `acmeco.optable.co` => `acmeco`.
     @objc
-    public var tenant: String
+    public var tenant: String {
+        get { tenantStore.withLock { $0 } }
+        set { tenantStore.withLock { $0 = newValue } }
+    }
+    private let tenantStore: Locked<String>
 
     /// The DCN's Source Slug. E.g. `acmeco-sdk`.
     @objc
-    public var originSlug: String
+    public var originSlug: String {
+        get { originSlugStore.withLock { $0 } }
+        set { originSlugStore.withLock { $0 = newValue } }
+    }
+    private let originSlugStore: Locked<String>
 
     // MARK: Optional
     /// The hostname of the Optable endpoint. Default value is "na.edge.optable.co".
     @objc
-    public var host: String = "na.edge.optable.co"
+    public var host: String {
+        get { hostStore.withLock { $0 } }
+        set { hostStore.withLock { $0 = newValue } }
+    }
+    private let hostStore = Locked("na.edge.optable.co")
 
     /// The API path to be appended to the host. Default value is "v2".
     @objc
-    public var path: String = "v2"
+    public var path: String {
+        get { pathStore.withLock { $0 } }
+        set { pathStore.withLock { $0 = newValue } }
+    }
+    private let pathStore = Locked("v2")
 
     /// Boolean flag that determines if insecure HTTP should be used instead of HTTPS. Default is false.
     @objc
-    public var insecure: Bool = false
+    public var insecure: Bool {
+        get { insecureStore.withLock { $0 } }
+        set { insecureStore.withLock { $0 = newValue } }
+    }
+    private let insecureStore = Locked(false)
 
     /// An optional API key for authentication. If the API Endpoint is enabled as private, a Service Account API key will be required.
     @objc
-    public var apiKey: String?
+    public var apiKey: String? {
+        get { apiKeyStore.withLock { $0 } }
+        set { apiKeyStore.withLock { $0 = newValue } }
+    }
+    private let apiKeyStore = Locked<String?>(nil)
 
     /// An optional custom user agent string for network requests.
     @objc
-    public var customUserAgent: String?
+    public var customUserAgent: String? {
+        get { customUserAgentStore.withLock { $0 } }
+        set { customUserAgentStore.withLock { $0 = newValue } }
+    }
+    private let customUserAgentStore = Locked<String?>(nil)
 
     /// An optional value sent as the `Origin` HTTP header on every Optable API request,
     /// identifying the origin you want your mobile traffic attributed to. E.g. `https://www.acmeco.com`.
     /// When `nil` (the default), no `Origin` header is sent. Unrelated to `originSlug`.
     @objc
-    public var origin: String?
+    public var origin: String? {
+        get { originStore.withLock { $0 } }
+        set { originStore.withLock { $0 = newValue } }
+    }
+    private let originStore = Locked<String?>(nil)
 
     /// Boolean flag to skip the detection of advertising IDs. Default is false.
     @objc
-    public var skipAdvertisingIdDetection: Bool = false
+    public var skipAdvertisingIdDetection: Bool {
+        get { skipAdvertisingIdDetectionStore.withLock { $0 } }
+        set { skipAdvertisingIdDetectionStore.withLock { $0 = newValue } }
+    }
+    private let skipAdvertisingIdDetectionStore = Locked(false)
 
     /**
      How long, in seconds, targeting data cached by the `targeting` API stays valid. Default is `defaultCacheTTL` (24 hours).
@@ -62,14 +104,22 @@ public class OptableConfig: NSObject {
      A value of `0` therefore disables caching entirely.
      */
     @objc
-    public var cacheTTL: TimeInterval = OptableConfig.defaultCacheTTL
+    public var cacheTTL: TimeInterval {
+        get { cacheTTLStore.withLock { $0 } }
+        set { cacheTTLStore.withLock { $0 = newValue } }
+    }
+    private let cacheTTLStore = Locked(OptableConfig.defaultCacheTTL)
 
     // MARK: Privacy Regulations
     /**
      Optable privacy regulation override, which can be one of: gdpr, can, us, or null and will override all other privacy regulations when present.
      */
     @objc
-    public var reg: String?
+    public var reg: String? {
+        get { regStore.withLock { $0 } }
+        set { regStore.withLock { $0 = newValue } }
+    }
+    private let regStore = Locked<String?>(nil)
 
     /**
      TCF EU v2 consent string.
@@ -77,7 +127,11 @@ public class OptableConfig: NSObject {
      > If not set, SDK will try to fetch data from UserDefaults => `IABTCF_TCString`, as stated in [](https://github.com/InteractiveAdvertisingBureau/GDPR-Transparency-and-Consent-Framework/blob/master/TCFv2/IAB%20Tech%20Lab%20-%20CMP%20API%20v2.md#in-app-details)
      */
     @objc
-    public var gdprConsent: String?
+    public var gdprConsent: String? {
+        get { gdprConsentStore.withLock { $0 } }
+        set { gdprConsentStore.withLock { $0 = newValue } }
+    }
+    private let gdprConsentStore = Locked<String?>(nil)
 
     /**
      A boolean indicating whether GDPR applies, represented as a integer (0 when it does not apply, 1 when it does). This value should be present when gdpr_consent is supplied.
@@ -85,7 +139,11 @@ public class OptableConfig: NSObject {
      > If not set, SDK will try to fetch data from UserDefaults => `IABTCF_gdprApplies`, as stated in [](https://github.com/InteractiveAdvertisingBureau/GDPR-Transparency-and-Consent-Framework/blob/master/TCFv2/IAB%20Tech%20Lab%20-%20CMP%20API%20v2.md#in-app-details)
      */
     @objc
-    public var gdpr: NSNumber?
+    public var gdpr: NSNumber? {
+        get { gdprStore.withLock { $0 } }
+        set { gdprStore.withLock { $0 = newValue } }
+    }
+    private let gdprStore = Locked<NSNumber?>(nil)
 
     /**
      GPP privacy string.
@@ -93,13 +151,21 @@ public class OptableConfig: NSObject {
      > If not set, SDK will try to fetch data from UserDefaults => `IABGPP_2_TCString`, as stated in [](https://github.com/InteractiveAdvertisingBureau/GDPR-Transparency-and-Consent-Framework/blob/master/TCFv2/IAB%20Tech%20Lab%20-%20CMP%20API%20v2.md#in-app-details)
      */
     @objc
-    public var gpp: String?
+    public var gpp: String? {
+        get { gppStore.withLock { $0 } }
+        set { gppStore.withLock { $0 = newValue } }
+    }
+    private let gppStore = Locked<String?>(nil)
 
     /**
      A comma-separated list of up to two sections applicable in a given GPP privacy string. This value is required when gpp is present.
      */
     @objc
-    public var gppSid: String?
+    public var gppSid: String? {
+        get { gppSidStore.withLock { $0 } }
+        set { gppSidStore.withLock { $0 = newValue } }
+    }
+    private let gppSidStore = Locked<String?>(nil)
 
     // MARK: Inits
     /**
@@ -109,8 +175,8 @@ public class OptableConfig: NSObject {
      */
     @objc
     public init(tenant: String, originSlug: String) {
-        self.tenant = tenant
-        self.originSlug = originSlug
+        self.tenantStore = Locked(tenant)
+        self.originSlugStore = Locked(originSlug)
         super.init()
     }
 
@@ -139,8 +205,9 @@ public class OptableConfig: NSObject {
         skipAdvertisingIdDetection: Bool = false,
         cacheTTL: TimeInterval = OptableConfig.defaultCacheTTL
     ) {
-        self.tenant = tenant
-        self.originSlug = originSlug
+        self.tenantStore = Locked(tenant)
+        self.originSlugStore = Locked(originSlug)
+        super.init()
         self.host = host
         self.path = path
         self.insecure = insecure

From c4f64966f40be5d003e3f40b76237843a462df55 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Thu, 1 Oct 2026 12:52:08 +0300
Subject: [PATCH 17/23] Deliver OptableDelegate callbacks on the main actor

---
 Source/OptableSDK.swift                       | 26 ++++++++++++-------
 .../Public/ObjCSupport/OptableSDK+ObjC.swift  | 24 ++++++++++-------
 2 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index b3aa88f..d6a8dc5 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -11,6 +11,7 @@ import Foundation
 // MARK: - OptableDelegate
 /**
  OptableDelegate enables Objective-C and Swift apps to receive results via delegate callbacks.
+ Every callback is delivered on the main actor (the main thread).
 
  - Ok callbacks:
    - identifyOk and witnessOk receive an HTTPURLResponse on success.
@@ -22,6 +23,7 @@ import Foundation
  If a synchronous error occurs while preparing a request, the method sets the passed NSError**
  and does not invoke the delegate callbacks.
  */
+@MainActor
 @objc
 public protocol OptableDelegate {
     func identifyOk(_ result: HTTPURLResponse)
@@ -225,11 +227,13 @@ public extension OptableSDK {
     @objc
     func witness(event: String, properties: [String: Any]) throws {
         try self.witness(event: event, properties: properties) { result in
-            switch result {
-            case let .success(response):
-                self.delegate?.witnessOk(response)
-            case let .failure(error as NSError):
-                self.delegate?.witnessErr(error)
+            Task { @MainActor in
+                switch result {
+                case let .success(response):
+                    self.delegate?.witnessOk(response)
+                case let .failure(error as NSError):
+                    self.delegate?.witnessErr(error)
+                }
             }
         }
     }
@@ -276,11 +280,13 @@ public extension OptableSDK {
     @objc
     func profile(traits: [String: Any], id: String? = nil, neighbors: [String]? = nil) throws {
         try _profile(traits: traits, id: id, neighbors: neighbors, completion: { result in
-            switch result {
-            case let .success(response):
-                self.delegate?.profileOk(response)
-            case let .failure(error as NSError):
-                self.delegate?.profileErr(error)
+            Task { @MainActor in
+                switch result {
+                case let .success(response):
+                    self.delegate?.profileOk(response)
+                case let .failure(error as NSError):
+                    self.delegate?.profileErr(error)
+                }
             }
         })
     }
diff --git a/Source/Public/ObjCSupport/OptableSDK+ObjC.swift b/Source/Public/ObjCSupport/OptableSDK+ObjC.swift
index 14ca848..b21899c 100644
--- a/Source/Public/ObjCSupport/OptableSDK+ObjC.swift
+++ b/Source/Public/ObjCSupport/OptableSDK+ObjC.swift
@@ -20,11 +20,13 @@ public extension OptableSDK {
     func identify(_ ids: [OptableSDKIdentifier]) throws {
         let bridgedIds = ids.compactMap({ OptableIdentifier(objc: $0) })
         try self._identify(bridgedIds) { result in
-            switch result {
-            case let .success(response):
-                self.delegate?.identifyOk(response)
-            case let .failure(error as NSError):
-                self.delegate?.identifyErr(error)
+            Task { @MainActor in
+                switch result {
+                case let .success(response):
+                    self.delegate?.identifyOk(response)
+                case let .failure(error as NSError):
+                    self.delegate?.identifyErr(error)
+                }
             }
         }
     }
@@ -54,11 +56,13 @@ public extension OptableSDK {
         let bridgedHIds = hids.compactMap({ OptableIdentifier(objc: $0) })
 
         try self._targeting(ids: bridgedIds, hids: bridgedHIds, completion: { result in
-            switch result {
-            case let .success(optableTargeting):
-                self.delegate?.targetingOk(optableTargeting)
-            case let .failure(error as NSError):
-                self.delegate?.targetingErr(error)
+            Task { @MainActor in
+                switch result {
+                case let .success(optableTargeting):
+                    self.delegate?.targetingOk(optableTargeting)
+                case let .failure(error as NSError):
+                    self.delegate?.targetingErr(error)
+                }
             }
         })
     }

From af482615f43695b655afaafa9d3e79441d41b96d Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Fri, 2 Oct 2026 10:26:52 +0300
Subject: [PATCH 18/23] Add preconcurrency to OptableDelegate

---
 Source/OptableSDK.swift | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index d6a8dc5..0cc3758 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -23,8 +23,7 @@ import Foundation
  If a synchronous error occurs while preparing a request, the method sets the passed NSError**
  and does not invoke the delegate callbacks.
  */
-@MainActor
-@objc
+@preconcurrency @MainActor @objc
 public protocol OptableDelegate {
     func identifyOk(_ result: HTTPURLResponse)
     func identifyErr(_ error: NSError)

From 389d26f047571ebe4d9ffcf133530ed180acfe83 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Fri, 2 Oct 2026 10:26:52 +0300
Subject: [PATCH 19/23] Isolate delegate to the main actor

---
 Source/OptableSDK.swift                 | 12 ++----------
 Tests/Integration/OptableSDKTests.swift |  3 ++-
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index 0cc3758..9b36aca 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -47,13 +47,8 @@ public protocol OptableDelegate {
  */
 @objc
 public class OptableSDK: NSObject {
-    @objc
-    public var delegate: OptableDelegate? {
-        get { delegateStore.withLock { $0 } }
-        set { delegateStore.withLock { $0 = newValue } }
-    }
-
-    private let delegateStore = Locked<OptableDelegate?>(nil)
+    @preconcurrency @MainActor @objc
+    public var delegate: OptableDelegate?
 
     let config: OptableConfig
     let api: EdgeAPI
@@ -79,9 +74,6 @@ public class OptableSDK: NSObject {
 }
 
 // MARK: - Sendable
-/// `@unchecked`: `delegate` is lock-guarded, `api` holds no mutable state beyond its lock-guarded user agent,
-/// and `config` is `Sendable`. Unchecked only because `OptableDelegate` is an `@objc` protocol whose conformers
-/// cannot be required to be `Sendable`.
 extension OptableSDK: @unchecked Sendable {}
 
 // MARK: - Identify
diff --git a/Tests/Integration/OptableSDKTests.swift b/Tests/Integration/OptableSDKTests.swift
index f54a184..73130c7 100644
--- a/Tests/Integration/OptableSDKTests.swift
+++ b/Tests/Integration/OptableSDKTests.swift
@@ -19,7 +19,8 @@ class OptableSDKTests: XCTestCase {
     lazy var witnessExpectation = expectation(description: "witness-delegate-expectation")
     lazy var profileExpectation = expectation(description: "profile-delegate-expectation")
 
-    override func setUpWithError() throws {
+    @MainActor
+    override func setUp() async throws {
         sdk.delegate = self
     }
 

From 024c2f52311c299f9bde695b83aabb130fe0208a Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Fri, 2 Oct 2026 10:26:53 +0300
Subject: [PATCH 20/23] Add preconcurrency to completion-based APIs

---
 Source/OptableSDK.swift | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index 9b36aca..6a760fe 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -95,6 +95,7 @@ public extension OptableSDK {
      }
      ```
      */
+    @preconcurrency
     func identify(_ ids: [OptableIdentifier], completion: @escaping @Sendable (Result<HTTPURLResponse, Error>) -> Void) throws {
         try _identify(ids, completion: completion)
     }
@@ -141,6 +142,7 @@ public extension OptableSDK {
      On success, the result is cached in client storage. You can read it using targetingFromCache()
      and clear it using targetingClearCache().
      */
+    @preconcurrency
     func targeting(_ ids: [OptableIdentifier]? = nil, hids: [OptableIdentifier]? = nil, completion: @escaping @Sendable (Result<OptableTargeting, Error>) -> Void) throws {
         try _targeting(ids: ids, hids: hids, completion: completion)
     }
@@ -189,6 +191,7 @@ public extension OptableSDK {
      - .success(HTTPURLResponse) on success
      - .failure(Error) on failure
      */
+    @preconcurrency
     func witness(event: String, properties: [String: Any], _ completion: @escaping @Sendable (Result<HTTPURLResponse, Error>) -> Void) throws {
         try _witness(event: event, properties: properties, completion: completion)
     }
@@ -242,6 +245,7 @@ public extension OptableSDK {
 
      The resulting OptableTargeting is also cached for targetingFromCache().
      */
+    @preconcurrency
     func profile(traits: [String: Any], id: String? = nil, neighbors: [String]? = nil, _ completion: @escaping @Sendable (Result<OptableTargeting, Error>) -> Void) throws {
         try _profile(traits: traits, id: id, neighbors: neighbors, completion: completion)
     }

From 3b9a8f13ff91670f9d5db774abc63815b3950023 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Fri, 2 Oct 2026 10:26:53 +0300
Subject: [PATCH 21/23] Raise test target deployment target to 17.0

---
 OptableSDK.xcodeproj/project.pbxproj | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/OptableSDK.xcodeproj/project.pbxproj b/OptableSDK.xcodeproj/project.pbxproj
index 2937569..0efcc66 100644
--- a/OptableSDK.xcodeproj/project.pbxproj
+++ b/OptableSDK.xcodeproj/project.pbxproj
@@ -431,7 +431,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Tests/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 17.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -452,7 +452,7 @@
 				CODE_SIGN_STYLE = Automatic;
 				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = Tests/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 17.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",

From 07799b75270f64c51604f2626018801df72ef46e Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Fri, 2 Oct 2026 10:26:53 +0300
Subject: [PATCH 22/23] Remove OptableTargeting Sendable comment

---
 Source/Public/OptableTargeting.swift | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Source/Public/OptableTargeting.swift b/Source/Public/OptableTargeting.swift
index e47ca1c..03f5286 100644
--- a/Source/Public/OptableTargeting.swift
+++ b/Source/Public/OptableTargeting.swift
@@ -34,8 +34,6 @@ public class OptableTargeting: NSObject {
 }
 
 // MARK: - Sendable
-/// Every stored property is a `let`, and the dictionaries only hold the immutable Foundation values
-/// produced by `JSONSerialization`, so instances can safely cross threads (e.g. resume a continuation).
 extension OptableTargeting: @unchecked Sendable {}
 
 // MARK: - Helpers

From 79657a57d6d031e5b315bd20455c5f1b8e246d85 Mon Sep 17 00:00:00 2001
From: Olena Stepaniuk <olena.stepaniuk@postindustria.com>
Date: Fri, 2 Oct 2026 11:52:28 +0300
Subject: [PATCH 23/23] Make EdgeAPI, OptableSDK Sendable

---
 Source/Core/EdgeAPI.swift            | 2 +-
 Source/OptableSDK.swift              | 4 ++--
 Source/Public/OptableTargeting.swift | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/Source/Core/EdgeAPI.swift b/Source/Core/EdgeAPI.swift
index 2f3a19b..4e01d3b 100644
--- a/Source/Core/EdgeAPI.swift
+++ b/Source/Core/EdgeAPI.swift
@@ -16,7 +16,7 @@ import WebKit
  [](https://docs.optable.co/optable-documentation/guides/real-time-api-integrations-guide)
 
  */
-final class EdgeAPI {
+final class EdgeAPI: Sendable {
     private static let kPassportHeader: String = "X-Optable-Visitor"
 
     let storage: LocalStorage
diff --git a/Source/OptableSDK.swift b/Source/OptableSDK.swift
index 6a760fe..4262047 100644
--- a/Source/OptableSDK.swift
+++ b/Source/OptableSDK.swift
@@ -46,7 +46,7 @@ public protocol OptableDelegate {
  The OptableSDK keeps some state in [UserDefaults](https://developer.apple.com/documentation/foundation/userdefaults), a key/value store persisted across launches of the app.  The state is therefore unique to the app+device, and not globally unique to the app across devices.
  */
 @objc
-public class OptableSDK: NSObject {
+public final class OptableSDK: NSObject {
     @preconcurrency @MainActor @objc
     public var delegate: OptableDelegate?
 
@@ -74,7 +74,7 @@ public class OptableSDK: NSObject {
 }
 
 // MARK: - Sendable
-extension OptableSDK: @unchecked Sendable {}
+extension OptableSDK: Sendable {}
 
 // MARK: - Identify
 public extension OptableSDK {
diff --git a/Source/Public/OptableTargeting.swift b/Source/Public/OptableTargeting.swift
index 03f5286..739fd4b 100644
--- a/Source/Public/OptableTargeting.swift
+++ b/Source/Public/OptableTargeting.swift
@@ -8,7 +8,7 @@
 import Foundation
 
 @objcMembers
-public class OptableTargeting: NSObject {
+public final class OptableTargeting: NSObject {
     public let targetingData: [String: Any]
     public let gamTargetingKeywords: [String: Any]?
     public let ortb2: String?