diff --git a/src/UglyToad.PdfPig/UglyToad.PdfPig.csproj b/src/UglyToad.PdfPig/UglyToad.PdfPig.csproj
index 6cb92585..f784e344 100644
--- a/src/UglyToad.PdfPig/UglyToad.PdfPig.csproj
+++ b/src/UglyToad.PdfPig/UglyToad.PdfPig.csproj
@@ -7,6 +7,7 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\pdfpig.snk</AssemblyOriginatorKeyFile>
+    <Nullable>annotations</Nullable>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard2.0|AnyCPU'">
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>