diff --git a/X10D.Tests/X10D.Tests.csproj b/X10D.Tests/X10D.Tests.csproj
index 9d86bf2..69ae0a2 100644
--- a/X10D.Tests/X10D.Tests.csproj
+++ b/X10D.Tests/X10D.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFrameworks>net7.0;net6.0;netstandard2.1</TargetFrameworks>
+        <TargetFrameworks>net7.0;net6.0</TargetFrameworks>
         <LangVersion>10.0</LangVersion>
         <IsPackable>false</IsPackable>
         <Nullable>enable</Nullable>