diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c72aa76..4635e1a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -18,15 +18,15 @@ jobs:
         with:
           submodules: true
 
-      - name: Setup .NET Core SDK
+      - name: Setup .NET 8 SDK
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: "3.1.x"
+          dotnet-version: "8.0.x"
 
-      - name: Setup .NET 6 SDK
+      - name: Setup .NET 9 SDK
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: "6.0.x"
+          dotnet-version: "9.0.x"
 
       - name: Test
         run: dotnet test --collect:"XPlat Code Coverage"
diff --git a/samples/ProblemDetails.MinimalApiSample/ProblemDetails.MinimalApiSample.csproj b/samples/ProblemDetails.MinimalApiSample/ProblemDetails.MinimalApiSample.csproj
index 6bd4760..28cd120 100644
--- a/samples/ProblemDetails.MinimalApiSample/ProblemDetails.MinimalApiSample.csproj
+++ b/samples/ProblemDetails.MinimalApiSample/ProblemDetails.MinimalApiSample.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <AssemblyName>Hellang.Middleware.ProblemDetails.MinimalApiSample</AssemblyName>
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.2.3" />
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="7.0.0" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/samples/ProblemDetails.Mvc.Sample/ProblemDetails.Mvc.Sample.csproj b/samples/ProblemDetails.Mvc.Sample/ProblemDetails.Mvc.Sample.csproj
index e442c55..88a6c2a 100644
--- a/samples/ProblemDetails.Mvc.Sample/ProblemDetails.Mvc.Sample.csproj
+++ b/samples/ProblemDetails.Mvc.Sample/ProblemDetails.Mvc.Sample.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
   </PropertyGroup>
diff --git a/samples/SpaFallback.Sample/SpaFallback.Sample.csproj b/samples/SpaFallback.Sample/SpaFallback.Sample.csproj
index 7a2b3ca..d509c99 100644
--- a/samples/SpaFallback.Sample/SpaFallback.Sample.csproj
+++ b/samples/SpaFallback.Sample/SpaFallback.Sample.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
   </PropertyGroup>
diff --git a/src/Authentication.JwtBearer.Google/Authentication.JwtBearer.Google.csproj b/src/Authentication.JwtBearer.Google/Authentication.JwtBearer.Google.csproj
index b345f3e..d18f7c7 100644
--- a/src/Authentication.JwtBearer.Google/Authentication.JwtBearer.Google.csproj
+++ b/src/Authentication.JwtBearer.Google/Authentication.JwtBearer.Google.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Version>3.0.0</Version>
-    <TargetFrameworks>netstandard2.0;net8.0</TargetFrameworks>
+    <Version>3.1.0</Version>
+    <TargetFrameworks>netstandard2.0;net8.0;net9.0</TargetFrameworks>
     <AssemblyName>Hellang.Authentication.JwtBearer.Google</AssemblyName>
     <RootNamespace>Hellang.Authentication.JwtBearer.Google</RootNamespace>
     <Description>JWT Bearer authentication for Google tokens</Description>
@@ -17,4 +17,10 @@
     <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.10" />
     <PackageReference Include="Microsoft.IdentityModel.Protocols.OpenIdConnect" Version="8.1.2" />
   </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="9.0.0" />
+    <PackageReference Include="Microsoft.IdentityModel.Protocols.OpenIdConnect" Version="8.2.0" />
+  </ItemGroup>
+  
 </Project>
diff --git a/src/ProblemDetails/ProblemDetails.csproj b/src/ProblemDetails/ProblemDetails.csproj
index 1ded11b..10b422f 100644
--- a/src/ProblemDetails/ProblemDetails.csproj
+++ b/src/ProblemDetails/ProblemDetails.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Version>7.0.0</Version>
-    <TargetFrameworks>net8.0</TargetFrameworks>
+    <Version>7.1.0</Version>
+    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
     <AssemblyName>Hellang.Middleware.ProblemDetails</AssemblyName>
     <RootNamespace>Hellang.Middleware.ProblemDetails</RootNamespace>
     <Description>Error handling middleware, using RFC7807</Description>
@@ -24,7 +24,12 @@
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
     <PackageReference Include="System.Reflection.Metadata" Version="8.0.1" />
   </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+    <PackageReference Include="System.Reflection.Metadata" Version="9.0.0" />
+  </ItemGroup>
+  
 </Project>
diff --git a/src/RateLimiting/RateLimiting.csproj b/src/RateLimiting/RateLimiting.csproj
index 943d238..3ddbd7b 100644
--- a/src/RateLimiting/RateLimiting.csproj
+++ b/src/RateLimiting/RateLimiting.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Version>2.0.0-alpha.1</Version>
-    <TargetFrameworks>netstandard2.0;net8.0</TargetFrameworks>
+    <Version>2.1.0-alpha.1</Version>
+    <TargetFrameworks>netstandard2.0;net8.0;net9.0</TargetFrameworks>
     <AssemblyName>Hellang.Middleware.RateLimiting</AssemblyName>
     <RootNamespace>Hellang.Middleware.RateLimiting</RootNamespace>
     <Description>Rate-limiting middleware using ASP.NET Core's IDistributedCache.</Description>
@@ -18,4 +18,9 @@
   <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>
+  
+  <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
+  
 </Project>
diff --git a/src/SpaFallback/SpaFallback.csproj b/src/SpaFallback/SpaFallback.csproj
index 6ab283e..9aa9e97 100644
--- a/src/SpaFallback/SpaFallback.csproj
+++ b/src/SpaFallback/SpaFallback.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Version>3.0.0</Version>
-    <TargetFrameworks>net8.0</TargetFrameworks>
+    <Version>3.1.0</Version>
+    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
     <AssemblyName>Hellang.Middleware.SpaFallback</AssemblyName>
     <RootNamespace>Hellang.Middleware.SpaFallback</RootNamespace>
     <Description>SPA fallback middleware for client-side routing</Description>
diff --git a/test/Directory.Build.props b/test/Directory.Build.props
index 5ca163d..fbc0b17 100644
--- a/test/Directory.Build.props
+++ b/test/Directory.Build.props
@@ -3,14 +3,14 @@
     <OutputType>Exe</OutputType>
     <IsPackable>False</IsPackable>
     <LangVersion>9.0</LangVersion>
-    <TargetFrameworks>net8.0</TargetFrameworks>
+    <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
     <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="8.0.10" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
     <PackageReference Include="xunit" Version="2.4.1" />
@@ -20,4 +20,16 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
     </PackageReference>
   </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
+    <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="9.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+    <PackageReference Include="coverlet.collector" Version="6.0.2">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+  
 </Project>