diff --git a/src/Directory.Build.props b/src/Directory.Build.props
index 175c2e0..62b67d6 100644
--- a/src/Directory.Build.props
+++ b/src/Directory.Build.props
@@ -20,7 +20,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="Polyfill" Version="9.11.0" Condition="!Exists('packages.config')">
+    <PackageReference Include="Polyfill" Version="9.15.0" Condition="!Exists('packages.config')">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
diff --git a/tests/Directory.Build.props b/tests/Directory.Build.props
index ff2dcff..91304b4 100644
--- a/tests/Directory.Build.props
+++ b/tests/Directory.Build.props
@@ -16,7 +16,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageReference Include="Shouldly" Version="4.*" />
     <PackageReference Include="TUnit" Version="1.*" />
-    <PackageReference Include="Polyfill" Version="9.11.0">
+    <PackageReference Include="Polyfill" Version="9.15.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>