diff --git a/src/GraphQL.Authorization.Tests/GraphQL.Authorization.Tests.csproj b/src/GraphQL.Authorization.Tests/GraphQL.Authorization.Tests.csproj
index a3df79c..daa8393 100644
--- a/src/GraphQL.Authorization.Tests/GraphQL.Authorization.Tests.csproj
+++ b/src/GraphQL.Authorization.Tests/GraphQL.Authorization.Tests.csproj
@@ -11,6 +11,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="GraphQL.NewtonsoftJson" Version="3.0.0-preview-1648" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
     <PackageReference Include="Shouldly" Version="3.0.2" />
     <PackageReference Include="xunit" Version="2.4.1" />
diff --git a/src/GraphQL.Authorization.Tests/ValidationTestBase.cs b/src/GraphQL.Authorization.Tests/ValidationTestBase.cs
index 15d0435..ee2b4e4 100644
--- a/src/GraphQL.Authorization.Tests/ValidationTestBase.cs
+++ b/src/GraphQL.Authorization.Tests/ValidationTestBase.cs
@@ -2,13 +2,11 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Security.Claims;
-using GraphQL;
 using GraphQL.Execution;
-using GraphQL.Http;
+using GraphQL.NewtonsoftJson;
 using GraphQL.Types;
 using GraphQL.Validation;
 using Shouldly;
-using Xunit;
 
 namespace GraphQL.Authorization.Tests
 {
@@ -30,7 +28,7 @@ public void Rule(params IValidationRule[] rules)
 
     public class GraphQLUserContext : Dictionary<string, object>, IProvideClaimsPrincipal
     {
-        public ClaimsPrincipal User { get; set;}
+        public ClaimsPrincipal User { get; set; }
     }
 
     public class ValidationTestBase
diff --git a/src/GraphQL.Authorization/AuthorizationContext.cs b/src/GraphQL.Authorization/AuthorizationContext.cs
index bf9246c..4e02981 100644
--- a/src/GraphQL.Authorization/AuthorizationContext.cs
+++ b/src/GraphQL.Authorization/AuthorizationContext.cs
@@ -12,7 +12,7 @@ public class AuthorizationContext
 
         public object UserContext { get; set; }
 
-        public Dictionary<string, object> InputVariables { get; set; }
+        public IDictionary<string, object> InputVariables { get; set; }
 
         public IEnumerable<string> Errors => _errors;
 
diff --git a/src/GraphQL.Authorization/AuthorizationEvaluator.cs b/src/GraphQL.Authorization/AuthorizationEvaluator.cs
index 1b2564e..dbe7106 100644
--- a/src/GraphQL.Authorization/AuthorizationEvaluator.cs
+++ b/src/GraphQL.Authorization/AuthorizationEvaluator.cs
@@ -10,7 +10,7 @@ public interface IAuthorizationEvaluator
         Task<AuthorizationResult> Evaluate(
             ClaimsPrincipal principal,
             object userContext,
-            Dictionary<string, object> arguments,
+            IDictionary<string, object> arguments,
             IEnumerable<string> requiredPolicies);
     }
 
@@ -26,7 +26,7 @@ public AuthorizationEvaluator(AuthorizationSettings settings)
         public async Task<AuthorizationResult> Evaluate(
             ClaimsPrincipal principal,
             object userContext,
-            Dictionary<string, object> inputVariables,
+            IDictionary<string, object> inputVariables,
             IEnumerable<string> requiredPolicies)
         {
             var context = new AuthorizationContext();
diff --git a/src/GraphQL.Authorization/AuthorizationMetadataExtensions.cs b/src/GraphQL.Authorization/AuthorizationMetadataExtensions.cs
index e0912f5..10759df 100644
--- a/src/GraphQL.Authorization/AuthorizationMetadataExtensions.cs
+++ b/src/GraphQL.Authorization/AuthorizationMetadataExtensions.cs
@@ -20,7 +20,7 @@ public static Task<AuthorizationResult> Authorize(
             this IProvideMetadata type,
             ClaimsPrincipal principal,
             object userContext,
-            Dictionary<string, object> inputVariables,
+            IDictionary<string, object> inputVariables,
             IAuthorizationEvaluator evaluator)
         {
             var list = GetPolicies(type);
diff --git a/src/GraphQL.Authorization/AuthorizationValidationRule.cs b/src/GraphQL.Authorization/AuthorizationValidationRule.cs
index 97220a8..a14d52d 100644
--- a/src/GraphQL.Authorization/AuthorizationValidationRule.cs
+++ b/src/GraphQL.Authorization/AuthorizationValidationRule.cs
@@ -1,4 +1,3 @@
-using System.Linq;
 using System.Threading.Tasks;
 using GraphQL.Language.AST;
 using GraphQL.Types;
diff --git a/src/GraphQL.Authorization/GraphQL.Authorization.csproj b/src/GraphQL.Authorization/GraphQL.Authorization.csproj
index 283d56f..681a970 100644
--- a/src/GraphQL.Authorization/GraphQL.Authorization.csproj
+++ b/src/GraphQL.Authorization/GraphQL.Authorization.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <Description>A toolset for authorizing access to graph types for GraphQL .NET</Description>
@@ -24,7 +24,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="GraphQL" Version="3.0.0-preview-1352" />
+    <PackageReference Include="GraphQL" Version="3.0.0-preview-1648" />
   </ItemGroup>
 
 </Project>
diff --git a/src/Harness/GraphQLAuthExtensions.cs b/src/Harness/GraphQLAuthExtensions.cs
index cb9d253..7da838f 100644
--- a/src/Harness/GraphQLAuthExtensions.cs
+++ b/src/Harness/GraphQLAuthExtensions.cs
@@ -4,7 +4,6 @@
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using GraphQL.Authorization;
 using GraphQL.Validation;
-using System.Threading.Tasks;
 
 namespace Harness
 {
diff --git a/src/Harness/Harness.csproj b/src/Harness/Harness.csproj
index f6615e9..b6328ac 100644
--- a/src/Harness/Harness.csproj
+++ b/src/Harness/Harness.csproj
@@ -13,7 +13,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="GraphQL" Version="3.0.0-preview-1352" />
+    <PackageReference Include="GraphQL" Version="3.0.0-preview-1648" />
     <PackageReference Include="GraphQL.Server.Ui.GraphiQL" Version="3.5.0-alpha0027" />
     <PackageReference Include="GraphQL.Server.Transports.AspNetCore" Version="3.5.0-alpha0027" />
     <PackageReference Include="Microsoft.AspNetCore.All" />