diff --git a/src/Exercism.TestRunner.CSharp/Exercism.TestRunner.CSharp.csproj b/src/Exercism.TestRunner.CSharp/Exercism.TestRunner.CSharp.csproj
index f8b6373..8cb063e 100644
--- a/src/Exercism.TestRunner.CSharp/Exercism.TestRunner.CSharp.csproj
+++ b/src/Exercism.TestRunner.CSharp/Exercism.TestRunner.CSharp.csproj
@@ -14,13 +14,13 @@
     <PackageReference Include="CommandLineParser" Version="2.9.1" />
     <PackageReference Include="Exercism.Tests" Version="0.1.0-beta1" />
     <PackageReference Include="Humanizer.Core" Version="2.14.1" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.1.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.3.1" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
-    <PackageReference Include="xunit" Version="2.4.1" />
-    <PackageReference Include="xunit.runner.utility" Version="2.4.1" />
-    <PackageReference Include="FakeItEasy" Version="6.2.1" />
-    <PackageReference Include="FsCheck" Version="2.16.4" />
-    <PackageReference Include="FsCheck.Xunit" Version="2.16.4" />
+    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit.runner.utility" Version="2.4.2" />
+    <PackageReference Include="FakeItEasy" Version="7.3.1" />
+    <PackageReference Include="FsCheck" Version="2.16.5" />
+    <PackageReference Include="FsCheck.Xunit" Version="2.16.5" />
     <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
     <PackageReference Include="Sprache" Version="2.3.1" />
   </ItemGroup>
diff --git a/src/Exercism.TestRunner.CSharp/TestRunWriter.cs b/src/Exercism.TestRunner.CSharp/TestRunWriter.cs
index 668c906..f871901 100644
--- a/src/Exercism.TestRunner.CSharp/TestRunWriter.cs
+++ b/src/Exercism.TestRunner.CSharp/TestRunWriter.cs
@@ -19,7 +19,7 @@ private static JsonSerializerOptions CreateJsonSerializerOptions()
         {
             var options = new JsonSerializerOptions
             {
-                IgnoreNullValues = true,
+                DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
                 WriteIndented = true,
             };
             options.Converters.Add(new JsonStringEnumConverter(JsonNamingPolicy.CamelCase));
diff --git a/test/Exercism.TestRunner.CSharp.IntegrationTests/Exercism.TestRunner.CSharp.IntegrationTests.csproj b/test/Exercism.TestRunner.CSharp.IntegrationTests/Exercism.TestRunner.CSharp.IntegrationTests.csproj
index eae36af..89d9bca 100644
--- a/test/Exercism.TestRunner.CSharp.IntegrationTests/Exercism.TestRunner.CSharp.IntegrationTests.csproj
+++ b/test/Exercism.TestRunner.CSharp.IntegrationTests/Exercism.TestRunner.CSharp.IntegrationTests.csproj
@@ -6,8 +6,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
-    <PackageReference Include="xunit" Version="2.4.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.3.2" />
+    <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" />
   </ItemGroup>
 
diff --git a/test/Exercism.TestRunner.CSharp.IntegrationTests/TestRunResultReader.cs b/test/Exercism.TestRunner.CSharp.IntegrationTests/TestRunResultReader.cs
index f7ad8ef..1596a2a 100644
--- a/test/Exercism.TestRunner.CSharp.IntegrationTests/TestRunResultReader.cs
+++ b/test/Exercism.TestRunner.CSharp.IntegrationTests/TestRunResultReader.cs
@@ -40,7 +40,7 @@ private static JsonSerializerOptions CreateJsonSerializerOptions()
         {
             var options = new JsonSerializerOptions
             {
-                IgnoreNullValues = true,
+                DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
                 PropertyNamingPolicy = null
             };
             options.Converters.Add(new JsonStringEnumConverter());