diff --git a/Parser.Tests/Parser.Tests.csproj b/Parser.Tests/Parser.Tests.csproj
index 463a884..b0bbeec 100644
--- a/Parser.Tests/Parser.Tests.csproj
+++ b/Parser.Tests/Parser.Tests.csproj
@@ -2,7 +2,7 @@
   <PropertyGroup>
     <TargetFramework>netcoreapp3.0</TargetFramework>
     <IsPackable>false</IsPackable>
-    <NullableContextOptions>enable</NullableContextOptions>
+    <Nullable>enable</Nullable>
     <LangVersion>8.0</LangVersion>
   </PropertyGroup>
   <ItemGroup>
diff --git a/Parser/Parser.csproj b/Parser/Parser.csproj
index 122db84..be517b0 100644
--- a/Parser/Parser.csproj
+++ b/Parser/Parser.csproj
@@ -2,7 +2,7 @@
   <PropertyGroup>
     <TargetFramework>netcoreapp3.0</TargetFramework>
     <LangVersion>8.0</LangVersion>
-    <NullableContextOptions>enable</NullableContextOptions>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />