diff --git a/Doppler.FeatureToggle.Tests/Doppler.FeatureToggle.Tests.csproj b/Doppler.FeatureToggle.Tests/Doppler.FeatureToggle.Tests.csproj
index e739487..c91db20 100644
--- a/Doppler.FeatureToggle.Tests/Doppler.FeatureToggle.Tests.csproj
+++ b/Doppler.FeatureToggle.Tests/Doppler.FeatureToggle.Tests.csproj
@@ -31,7 +31,7 @@
     <PackageReference Include="System.ObjectModel" Version="4.3.0" />
     <PackageReference Include="System.Runtime.Serialization.Primitives" Version="4.3.0" />
     <PackageReference Include="System.Runtime.Serialization.Xml" Version="4.3.0" />
-    <PackageReference Include="System.Runtime.Serialization.Formatters" Version="4.3.0" />
+    <PackageReference Include="System.Runtime.Serialization.Formatters" Version="9.0.0" />
     <PackageReference Include="System.Xml.XmlSerializer" Version="4.3.0" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
     <PackageReference Include="xunit" Version="2.9.2" />
diff --git a/Doppler.FeatureToggle/Doppler.FeatureToggle.csproj b/Doppler.FeatureToggle/Doppler.FeatureToggle.csproj
index 35828c6..2c69d0d 100644
--- a/Doppler.FeatureToggle/Doppler.FeatureToggle.csproj
+++ b/Doppler.FeatureToggle/Doppler.FeatureToggle.csproj
@@ -46,7 +46,7 @@
     <PackageReference Include="System.Net.Requests" Version="4.3.0" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard1.3'">
-    <PackageReference Include="System.Runtime.Serialization.Formatters" Version="4.3.0" />
+    <PackageReference Include="System.Runtime.Serialization.Formatters" Version="9.0.0" />
     <PackageReference Include="System.Xml.XmlDocument" Version="4.3.0" />
   </ItemGroup>
   <ItemGroup>
diff --git a/global.json b/global.json
index 8c70738..6532452 100644
--- a/global.json
+++ b/global.json
@@ -1,5 +1,5 @@
 {
   "sdk": {
-    "version": "8.0.404"
+    "version": "9.0.100"
   }
 }