diff --git a/src/Bannerlord.ModuleManager/Bannerlord.ModuleManager.csproj b/src/Bannerlord.ModuleManager/Bannerlord.ModuleManager.csproj
index 62415b9..ff0d5e3 100644
--- a/src/Bannerlord.ModuleManager/Bannerlord.ModuleManager.csproj
+++ b/src/Bannerlord.ModuleManager/Bannerlord.ModuleManager.csproj
@@ -6,7 +6,7 @@
     <Nullable>enable</Nullable>
     <VersionOverride>0</VersionOverride>
     <Version>5.0.$(VersionOverride)</Version>
-    <DefineConstants>$(DefineConstants);BANNERLORDBUTRMODULEMANAGER_PUBLIC;BANNERLORDBUTRMODULEMANAGER_ENABLE_WARNING;</DefineConstants>
+    <DefineConstants>$(DefineConstants);BANNERLORDBUTRMODULEMANAGER_PUBLIC;BANNERLORDBUTRMODULEMANAGER_ENABLE_WARNING;BANNERLORDBUTRMODULEMANAGER_NULLABLE;</DefineConstants>
   </PropertyGroup>
 
   <!--NuGet Package-->
@@ -55,6 +55,9 @@
     <PackageFile Include="../Bannerlord.ModuleManager.Source.props" PackagePath="build/Bannerlord.ModuleManager.Source.props" />
     <PackageFile Include="../../resources/Butter.png" PackagePath="Butter.png" />
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Nullable" Version="1.3.1" PrivateAssets="all" IncludeAssets="runtime; build; native; contentfiles; analyzers; buildtransitive" />
+  </ItemGroup>
   <!--NuGet Package-->
 
 </Project>
\ No newline at end of file