diff --git a/Makefile b/Makefile
index d390bb16b8..9b39355a2a 100644
--- a/Makefile
+++ b/Makefile
@@ -107,6 +107,16 @@ oas-download: ## Downloads the latest App Store Connect OpenAPI specification do
 oas-patch: # Patches the OpenAPI specification document with the patches in Scripts/patch-oas.jq
 	@jq --from-file Scripts/patch-oas.jq "$(OAS_DOWNLOAD_OUTPUT)" > "$(OAS_DOWNLOAD_OUTPUT).tmp"
 	@mv "$(OAS_DOWNLOAD_OUTPUT).tmp" "$(OAS_DOWNLOAD_OUTPUT)"
+	@$(MAKE) --no-print-directory oas-validate
+
+oas-validate: ## Validates the OpenAPI specification document
+	@swift run \
+		--configuration release \
+		--package-path "$(OAS_GENERATE_TOOLS)" \
+		swift-openapi-generator generate \
+		--config "$(OAS_GENERATE_CONFIG)" \
+		--dry-run \
+		"$(OAS_DOWNLOAD_OUTPUT)"
 
 oas-generate: ## Generates the library source code from the OpenAPI specification document
 	@mkdir -p "$(OAS_GENERATE_OUTPUT)"
diff --git a/Package.swift b/Package.swift
index 387b20cc36..90585d1fb3 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,16 +1,18 @@
-// swift-tools-version: 5.10
+// swift-tools-version: 6.0
 
-//===----------------------------------------------------------------------===
+// ===----------------------------------------------------------------------===
 //
 // This source file is part of the ASConnectService open source project
 //
 // Copyright (c) 2026 Röck+Cöde VoF. and the ASConnectService project authors
-// Licensed under the EUPL 1.2 or later.
+// Licensed under Apache license v2.0
 //
 // See LICENSE for license information
 // See CONTRIBUTORS for the list of ASConnectService project authors
 //
-//===----------------------------------------------------------------------===
+// SPDX-License-Identifier: Apache-2.0
+//
+// ===----------------------------------------------------------------------===
 
 import class Foundation.ProcessInfo
 import PackageDescription
diff --git a/README.md b/README.md
index fc94c9795f..163903f59e 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Add `ASConnectService` as a dependency in your `Package.swift` file:
 
 ```swift
 dependencies: [
-    .package(url: "https://github.com/rock-n-code/asconnect-service.git", from: "1.0.0")
+    .package(url: "https://github.com/rock-n-code/asconnect-service.git", from: "2.0.0")
 ]
 ```
 
@@ -142,6 +142,9 @@ make oas-download
 
 # Regenerate the code only
 make oas-generate
+
+# Validate the specification only
+make oas-validate
 ```
 
 ## Dependencies
diff --git a/Tests/ASConnectService/Cases/Public/Extensions/PagedDocumentLinksTests.swift b/Tests/ASConnectService/Cases/Public/Extensions/PagedDocumentLinksTests.swift
index 79ca6b4e23..3d0ca05324 100644
--- a/Tests/ASConnectService/Cases/Public/Extensions/PagedDocumentLinksTests.swift
+++ b/Tests/ASConnectService/Cases/Public/Extensions/PagedDocumentLinksTests.swift
@@ -1,3 +1,17 @@
+// ===----------------------------------------------------------------------===
+//
+// This source file is part of the ASConnectService open source project
+//
+// Copyright (c) 2026 Röck+Cöde VoF. and the ASConnectService project authors
+// Licensed under Apache license v2.0
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of ASConnectService project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// ===----------------------------------------------------------------------===
+
 import Testing
 
 // A non-testable import ensures that the extension can be used from outside the module.
diff --git a/Tests/ASConnectService/Cases/Public/Middlewares/BearerAuthMiddlewareTests.swift b/Tests/ASConnectService/Cases/Public/Middlewares/BearerAuthMiddlewareTests.swift
index 71e94bfd06..64bf01cb9e 100644
--- a/Tests/ASConnectService/Cases/Public/Middlewares/BearerAuthMiddlewareTests.swift
+++ b/Tests/ASConnectService/Cases/Public/Middlewares/BearerAuthMiddlewareTests.swift
@@ -1,3 +1,17 @@
+// ===----------------------------------------------------------------------===
+//
+// This source file is part of the ASConnectService open source project
+//
+// Copyright (c) 2026 Röck+Cöde VoF. and the ASConnectService project authors
+// Licensed under Apache license v2.0
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of ASConnectService project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// ===----------------------------------------------------------------------===
+
 import Foundation
 import HTTPTypes
 import OpenAPIRuntime
diff --git a/Tests/ASConnectService/Cases/Public/Middlewares/RateLimitMiddlewareTests.swift b/Tests/ASConnectService/Cases/Public/Middlewares/RateLimitMiddlewareTests.swift
index bee86db761..6386ee4fe9 100644
--- a/Tests/ASConnectService/Cases/Public/Middlewares/RateLimitMiddlewareTests.swift
+++ b/Tests/ASConnectService/Cases/Public/Middlewares/RateLimitMiddlewareTests.swift
@@ -1,3 +1,17 @@
+// ===----------------------------------------------------------------------===
+//
+// This source file is part of the ASConnectService open source project
+//
+// Copyright (c) 2026 Röck+Cöde VoF. and the ASConnectService project authors
+// Licensed under Apache license v2.0
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of ASConnectService project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// ===----------------------------------------------------------------------===
+
 import Foundation
 import HTTPTypes
 import OpenAPIRuntime
diff --git a/Tests/ASConnectService/Cases/Public/Providers/APIKeyTokenProviderTests.swift b/Tests/ASConnectService/Cases/Public/Providers/APIKeyTokenProviderTests.swift
index 6d537d7845..e1f85268b7 100644
--- a/Tests/ASConnectService/Cases/Public/Providers/APIKeyTokenProviderTests.swift
+++ b/Tests/ASConnectService/Cases/Public/Providers/APIKeyTokenProviderTests.swift
@@ -1,3 +1,17 @@
+// ===----------------------------------------------------------------------===
+//
+// This source file is part of the ASConnectService open source project
+//
+// Copyright (c) 2026 Röck+Cöde VoF. and the ASConnectService project authors
+// Licensed under Apache license v2.0
+//
+// See LICENSE for license information
+// See CONTRIBUTORS for the list of ASConnectService project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// ===----------------------------------------------------------------------===
+
 #if canImport(CryptoKit)
 import CryptoKit
 import Foundation
@@ -96,9 +110,8 @@ private extension APIKeyTokenProviderTests {
         try #require(parts.count == 3)
 
         let header = try JSONDecoder().decode([String: String].self, from: try #require(Data(base64URL: parts[0])))
-        let payload = try #require(
-            try JSONSerialization.jsonObject(with: try #require(Data(base64URL: parts[1]))) as? [String: Any]
-        )
+        let payloadData = try #require(Data(base64URL: parts[1]))
+        let payload = try #require(try JSONSerialization.jsonObject(with: payloadData) as? [String: Any])
 
         return (header, payload)
     }
diff --git a/Tools/Package.swift b/Tools/Package.swift
index 1fe008d3d1..6688178f21 100644
--- a/Tools/Package.swift
+++ b/Tools/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.10
+// swift-tools-version: 6.0
 
 // ===----------------------------------------------------------------------===
 //