diff --git a/src/Turnierplan.Adapter.Test.Functional/TurnierplanAdapterTest.cs b/src/Turnierplan.Adapter.Test.Functional/TurnierplanAdapterTest.cs
index df3e5890..d2b79e60 100644
--- a/src/Turnierplan.Adapter.Test.Functional/TurnierplanAdapterTest.cs
+++ b/src/Turnierplan.Adapter.Test.Functional/TurnierplanAdapterTest.cs
@@ -348,7 +348,7 @@ public async Task Turnierplan_Client_Throws_Exception_When_Version_Does_Not_Matc
             _ = await client.GetTournament("x");
         };
 
-        var actualVersion = typeof(TurnierplanClient).Assembly.GetName().Version!.ToString();
+        var actualVersion = System.Text.RegularExpressions.Regex.Replace(typeof(TurnierplanClient).Assembly.GetName().Version!.ToString(), @"\.0$", string.Empty);
         var expectedMessage = sendHeader
             ? $"Server version '2024.0.0' does not match the Turnierplan.Adapter version '{actualVersion}'."
             : "Could not get 'X-Turnierplan-Version' header from response.";
diff --git a/src/Turnierplan.Adapter/TurnierplanClient.cs b/src/Turnierplan.Adapter/TurnierplanClient.cs
index 114af19a..d3913dc0 100644
--- a/src/Turnierplan.Adapter/TurnierplanClient.cs
+++ b/src/Turnierplan.Adapter/TurnierplanClient.cs
@@ -2,6 +2,7 @@
 using System.Net.Http.Json;
 using System.Text.Json;
 using System.Text.Json.Serialization;
+using System.Text.RegularExpressions;
 using Microsoft.AspNetCore.Http.Extensions;
 using Turnierplan.Adapter.Models;
 
@@ -16,9 +17,7 @@ public sealed class TurnierplanClient : IDisposable
     private const string ApiKeySecretHeaderName = "X-Api-Key-Secret";
     private const string TurnierplanVersionHeaderName = "X-Turnierplan-Version";
 
-    private static readonly string __turnierplanAdapterVersion =
-        typeof(TurnierplanClient).Assembly.GetName().Version?.ToString()
-            ?? throw new InvalidOperationException("Could not determine Turnierplan.Adapter version from assembly name.");
+    private static readonly string __turnierplanAdapterVersion = DetermineAdapterVersion();
 
     private static readonly JsonSerializerOptions __serializerOptions = new()
     {
@@ -118,6 +117,22 @@ public void Dispose()
         }
     }
 
+    private static string DetermineAdapterVersion()
+    {
+        var assemblyVersion = typeof(TurnierplanClient).Assembly.GetName().Version?.ToString();
+
+        if (assemblyVersion is null)
+        {
+            throw new InvalidOperationException("Could not determine Turnierplan.Adapter version from assembly name.");
+        }
+
+        var match = Regex.Match(assemblyVersion, @"^(?<Version>\d+\.\d+\.\d+)\.0$");
+
+        return match.Success
+            ? match.Groups["Version"].Value
+            : throw new InvalidOperationException("Could not determine Turnierplan.Adapter version from assembly name.");
+    }
+
     private static void VerifyServerVersion(HttpResponseMessage response)
     {
         if (!response.Headers.TryGetValues(TurnierplanVersionHeaderName, out var headerValue))
diff --git a/src/Turnierplan.App/Middlewares/TurnierplanVersionMiddleware.cs b/src/Turnierplan.App/Middlewares/TurnierplanVersionMiddleware.cs
new file mode 100644
index 00000000..0ed5c7b9
--- /dev/null
+++ b/src/Turnierplan.App/Middlewares/TurnierplanVersionMiddleware.cs
@@ -0,0 +1,18 @@
+using Turnierplan.App.Constants;
+
+namespace Turnierplan.App.Middlewares;
+
+internal sealed class TurnierplanVersionMiddleware(RequestDelegate next)
+{
+    private const string TurnierplanVersionHeaderName = "X-Turnierplan-Version";
+
+    public async Task InvokeAsync(HttpContext httpContext)
+    {
+        if (httpContext.User.Identity?.IsAuthenticated == true)
+        {
+            httpContext.Response.Headers.Append(TurnierplanVersionHeaderName, TurnierplanVersion.Version);
+        }
+
+        await next(httpContext);
+    }
+}
diff --git a/src/Turnierplan.App/Program.cs b/src/Turnierplan.App/Program.cs
index 34a2396d..070f34b4 100644
--- a/src/Turnierplan.App/Program.cs
+++ b/src/Turnierplan.App/Program.cs
@@ -8,6 +8,7 @@
 using Turnierplan.App.Extensions;
 using Turnierplan.App.Helpers;
 using Turnierplan.App.Mapping;
+using Turnierplan.App.Middlewares;
 using Turnierplan.App.OpenApi;
 using Turnierplan.App.Options;
 using Turnierplan.Dal.Extensions;
@@ -83,6 +84,8 @@
 app.UseAuthentication();
 app.UseAuthorization();
 
+app.UseMiddleware<TurnierplanVersionMiddleware>();
+
 app.Map(string.Empty, (HttpContext context) =>
 {
     context.Response.StatusCode = StatusCodes.Status303SeeOther;
diff --git a/src/Turnierplan.App/Security/ApiKeyAuthenticationHandler.cs b/src/Turnierplan.App/Security/ApiKeyAuthenticationHandler.cs
index beb3b6e2..737547a7 100644
--- a/src/Turnierplan.App/Security/ApiKeyAuthenticationHandler.cs
+++ b/src/Turnierplan.App/Security/ApiKeyAuthenticationHandler.cs
@@ -12,13 +12,9 @@ namespace Turnierplan.App.Security;
 
 internal sealed class ApiKeyAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
 {
+    private const string AuthenticationTypeName = "TurnierplanApiKeyAuthentication";
     private const string ApiKeyIdHeaderName = "x-api-key";
     private const string ApiKeySecretHeaderName = "x-api-key-secret";
-    private const string TurnierplanVersionHeaderName = "x-turnierplan-version";
-
-    private static readonly string __turnierplanVersion =
-        typeof(ApiKeyAuthenticationHandler).Assembly.GetName().Version?.ToString()
-            ?? throw new InvalidOperationException("Could not determine turnierplan.NET version from assembly name.");
 
     private readonly IApiKeyRepository _apiKeyRepository;
     private readonly IPasswordHasher<ApiKey> _secretHasher;
@@ -72,7 +68,7 @@ protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
 
         await _apiKeyRepository.UnitOfWork.SaveChangesAsync();
 
-        var identity = new ClaimsIdentity(claims: [
+        var identity = new ClaimsIdentity(authenticationType: AuthenticationTypeName, claims: [
             new Claim(ClaimTypes.PrincipalId, apiKey.PrincipalId.ToString()),
             new Claim(ClaimTypes.PrincipalKind, nameof(PrincipalKind.ApiKey))
         ]);
@@ -80,9 +76,6 @@ protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
         var principal = new ClaimsPrincipal([ identity ]);
         var ticket = new AuthenticationTicket(principal, Scheme.Name);
 
-        // Add the version as response header so that the Turnierplan.Adapter, if used, can detect a potential version mismatch
-        Context.Response.Headers.Append(TurnierplanVersionHeaderName, __turnierplanVersion);
-
         return AuthenticateResult.Success(ticket);
     }
 }