diff --git a/setup/docker/docker-compose.yml b/setup/docker/docker-compose.yml
index 74c7425..4d35736 100644
--- a/setup/docker/docker-compose.yml
+++ b/setup/docker/docker-compose.yml
@@ -4,7 +4,7 @@ services:
 
   main:
     container_name: nexus-main
-    image: mcr.microsoft.com/dotnet/sdk:6.0
+    image: mcr.microsoft.com/dotnet/sdk:7.0
     volumes:
       - /var/lib/nexus/docker/nexus-main/.ssh:/root/.ssh
     entrypoint: bash -c "cd; curl -s -O 'https://raw.githubusercontent.com/malstroem-labs/nexus-sources-remote/master/setup/docker/setup-main.sh'; source 'setup-main.sh'"
@@ -20,7 +20,7 @@ services:
 
   satellite-nexus:
     container_name: nexus-dotnet
-    image: mcr.microsoft.com/dotnet/sdk:6.0
+    image: mcr.microsoft.com/dotnet/sdk:7.0
     volumes:
       - /var/lib/nexus/docker/nexus-dotnet/.ssh:/root/.ssh
     entrypoint: bash -c "satellite_id=dotnet;cd; curl -s -O 'https://raw.githubusercontent.com/malstroem-labs/nexus-sources-remote/master/setup/docker/setup-satellite.sh'; source 'setup-satellite.sh'"
diff --git a/tests/Nexus.Sources.Remote.Tests/SetupDockerTests.cs b/tests/Nexus.Sources.Remote.Tests/SetupDockerTests.cs
index 59bb43f..2823f13 100644
--- a/tests/Nexus.Sources.Remote.Tests/SetupDockerTests.cs
+++ b/tests/Nexus.Sources.Remote.Tests/SetupDockerTests.cs
@@ -23,8 +23,8 @@ public async Task CanReadFullDay(string satelliteId, string command)
             await dataSource.SetContextAsync(context, NullLogger.Instance, CancellationToken.None);
 
             var catalog = await dataSource.GetCatalogAsync("/A/B/C", CancellationToken.None);
-            var resource = catalog.Resources!.First();
-            var representation = resource.Representations!.First();
+            var resource = catalog.Resources![0];
+            var representation = resource.Representations![0];
 
             var catalogItem = new CatalogItem(
                 catalog with { Resources = default! }, 
@@ -67,7 +67,7 @@ Task<ReadOnlyMemory<double>> ReadData(string resourcePath, DateTime begin, DateT
             Assert.True(expectedStatus.SequenceEqual(status.ToArray()));
         }
 
-        private DataSourceContext CreateContext(string satelliteId, string command)
+        private static DataSourceContext CreateContext(string satelliteId, string command)
         {
             return new DataSourceContext(
                 ResourceLocator: new Uri("https://example.com"),