diff --git a/tests/FrigateRelay.IntegrationTests/Fixtures/MosquittoFixture.cs b/tests/FrigateRelay.IntegrationTests/Fixtures/MosquittoFixture.cs
index c2f38d5..5941a8d 100644
--- a/tests/FrigateRelay.IntegrationTests/Fixtures/MosquittoFixture.cs
+++ b/tests/FrigateRelay.IntegrationTests/Fixtures/MosquittoFixture.cs
@@ -11,11 +11,14 @@ internal sealed class MosquittoFixture : IAsyncDisposable
     public MosquittoFixture()
     {
         var conf = "listener 1883\nallow_anonymous true\n";
-        _container = new ContainerBuilder()
-            .WithImage("eclipse-mosquitto:2")
+        // Testcontainers 4.10+ requires an explicit image at builder construction
+        // (parameterless ctor + chained .WithImage(...) is obsolete and slated for removal).
+        // The wait strategy renamed UntilPortIsAvailable → UntilExternalTcpPortIsAvailable
+        // in 4.7.0 and the old name was removed in a later patch; semantics still apply.
+        _container = new ContainerBuilder("eclipse-mosquitto:2")
             .WithPortBinding(1883, true)
             .WithResourceMapping(Encoding.UTF8.GetBytes(conf), "/mosquitto/config/mosquitto.conf")
-            .WithWaitStrategy(Wait.ForUnixContainer().UntilPortIsAvailable(1883))
+            .WithWaitStrategy(Wait.ForUnixContainer().UntilExternalTcpPortIsAvailable(1883))
             .Build();
     }
 
diff --git a/tests/FrigateRelay.IntegrationTests/FrigateRelay.IntegrationTests.csproj b/tests/FrigateRelay.IntegrationTests/FrigateRelay.IntegrationTests.csproj
index 6be9e1b..67ac6a4 100644
--- a/tests/FrigateRelay.IntegrationTests/FrigateRelay.IntegrationTests.csproj
+++ b/tests/FrigateRelay.IntegrationTests/FrigateRelay.IntegrationTests.csproj
@@ -16,7 +16,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="Testcontainers" Version="4.4.0" />
+    <PackageReference Include="Testcontainers" Version="4.11.0" />
     <PackageReference Include="WireMock.Net" Version="2.4.0" />
     <PackageReference Include="MQTTnet" Version="5.1.0.1559" />
     <!-- OpenTelemetry in-memory exporter — test-only, never in src/. Per PLAN-3.1 Task 3. -->