diff --git a/src/ConfigCat.Client.Tests/ConfigCat.Client.Tests.csproj b/src/ConfigCat.Client.Tests/ConfigCat.Client.Tests.csproj
index cf316138..e0c6aba6 100644
--- a/src/ConfigCat.Client.Tests/ConfigCat.Client.Tests.csproj
+++ b/src/ConfigCat.Client.Tests/ConfigCat.Client.Tests.csproj
@@ -23,7 +23,6 @@
     <PackageReference Include="MSTest.TestAdapter" Version="2.2.8" />
     <PackageReference Include="MSTest.TestFramework" Version="2.2.8" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />
-    <PackageReference Include="System.Text.RegularExpressions" Version="4.3.1" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/ConfigCatClient/ConfigCatClient.csproj b/src/ConfigCatClient/ConfigCatClient.csproj
index 2b7fec0c..9de220f4 100644
--- a/src/ConfigCatClient/ConfigCatClient.csproj
+++ b/src/ConfigCatClient/ConfigCatClient.csproj
@@ -57,7 +57,6 @@ Works with .NET, .NET Core, .NET Standard</Description>
   <ItemGroup>
     <PackageReference Include="System.Data.HashFunction.MurmurHash" Version="2.0.0" />
     <PackageReference Include="System.Net.Http" Version="4.3.4" />
-    <PackageReference Include="System.Text.RegularExpressions" Version="4.3.1" />
     <None Include="icon.png" Pack="true" Visible="false" PackagePath="" />
     <None Include="..\..\README.md" Pack="true" PackagePath="" />
   </ItemGroup>