diff --git a/src/FilterLists.Agent/Extensions/ReadOnlyListExtensions.cs b/src/FilterLists.Agent/Extensions/ReadOnlyListExtensions.cs
index 101ca01b0..46345eb4f 100644
--- a/src/FilterLists.Agent/Extensions/ReadOnlyListExtensions.cs
+++ b/src/FilterLists.Agent/Extensions/ReadOnlyListExtensions.cs
@@ -7,9 +7,7 @@ public static class ReadOnlyListExtensions
     {
         public static T FirstOrDefault<T>(this IReadOnlyList<T> list)
         {
-            if (list is null)
-                throw new ArgumentNullException(nameof(list));
-            return list.Count == 0 ? default : list[0];
+            return list.Count == 0 ? default! : list[0];
         }
     }
 }
\ No newline at end of file
diff --git a/src/FilterLists.Agent/FilterLists.Agent.csproj b/src/FilterLists.Agent/FilterLists.Agent.csproj
index dc05cae08..1d5cecf74 100644
--- a/src/FilterLists.Agent/FilterLists.Agent.csproj
+++ b/src/FilterLists.Agent/FilterLists.Agent.csproj
@@ -4,7 +4,9 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp2.2</TargetFramework>
     <TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>
-    <LangVersion>latest</LangVersion>
+    <LangVersion>8.0</LangVersion>
+    <Nullable>enable</Nullable>
+    <NullableContextOptions>enable</NullableContextOptions>
     <Authors>Collin M. Barrett</Authors>
     <Company>Collin M. Barrett</Company>
     <Product>FilterLists</Product>
diff --git a/src/FilterLists.Agent/FilterLists.Agent.ruleset b/src/FilterLists.Agent/FilterLists.Agent.ruleset
index 7ca8377c3..113f71758 100644
--- a/src/FilterLists.Agent/FilterLists.Agent.ruleset
+++ b/src/FilterLists.Agent/FilterLists.Agent.ruleset
@@ -13,6 +13,7 @@
     <Rule Id="CA1049" Action="Warning" />
     <Rule Id="CA1060" Action="Warning" />
     <Rule Id="CA1061" Action="Warning" />
+    <Rule Id="CA1062" Action="None" />
     <Rule Id="CA1063" Action="Warning" />
     <Rule Id="CA1065" Action="Warning" />
     <Rule Id="CA1301" Action="Warning" />