diff --git a/Src/Newtonsoft.Json.Tests/Issues/Issue1566.cs b/Src/Newtonsoft.Json.Tests/Issues/Issue1566.cs
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+#region License
+// Copyright (c) 2007 James Newton-King
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+#endregion
+
+#if !NET20
+using System;
+using System.Runtime.Serialization;
+using Newtonsoft.Json.Converters;
+#if DNXCORE50
+using System.Reflection;
+using Xunit;
+using Test = Xunit.FactAttribute;
+using Assert = Newtonsoft.Json.Tests.XUnitAssert;
+#else
+using NUnit.Framework;
+#endif
+
+namespace Newtonsoft.Json.Tests.Issues
+{
+    [TestFixture]
+    public class Issue1566 : TestFixtureBase
+    {
+        [Test]
+        public void Github_deserialize_pr_state_should_be_case_insensitive()
+        {
+            // Arrange
+            var jsonWithUppercase = "{\"state\": \"APPROVED\"}";
+            var jsonWithLowercase = "{\"state\": \"approved\"}";
+
+            // Act
+            var jsonObjectWithUppercase = JsonConvert.DeserializeObject<GitHubPullRequestReview>(jsonWithUppercase);
+            var jsonObjectWithLowercase = JsonConvert.DeserializeObject<GitHubPullRequestReview>(jsonWithLowercase);
+
+            // Assert
+            Assert.AreEqual(GitHubPullRequestReviewState.Approved, jsonObjectWithUppercase.State);
+            Assert.AreEqual(GitHubPullRequestReviewState.Approved, jsonObjectWithLowercase.State);
+        }
+
+        [Test]
+        public void Github_deserialize_pr_state_changes_requested_should_be_case_insensitive()
+        {
+            // Arrange
+            var jsonWithUppercase = "{\"state\": \"CHANGES_REQUESTED\"}";
+            var jsonWithLowercase = "{\"state\": \"changes_requested\"}";
+
+            // Act
+            var jsonObjectWithUppercase = JsonConvert.DeserializeObject<GitHubPullRequestReview>(jsonWithUppercase);
+            var jsonObjectWithLowercase = JsonConvert.DeserializeObject<GitHubPullRequestReview>(jsonWithLowercase);
+
+            // Assert
+            Assert.AreEqual(GitHubPullRequestReviewState.ChangesRequested, jsonObjectWithUppercase.State);
+            Assert.AreEqual(GitHubPullRequestReviewState.ChangesRequested, jsonObjectWithLowercase.State);
+        }
+
+        public enum GitHubPullRequestReviewState
+        {
+            [EnumMember(Value = "approved")]
+            Approved,
+
+            [EnumMember(Value = "changes_requested")]
+            ChangesRequested,
+
+            [EnumMember(Value = "commented")]
+            Commented,
+
+            [EnumMember(Value = "dismissed")]
+            Dismissed,
+
+            [EnumMember(Value = "pending")]
+            Pending
+        }
+
+        public class GitHubPullRequestReview
+        {
+            [JsonProperty("state")]
+            [JsonConverter(typeof(StringEnumConverter))]
+            public GitHubPullRequestReviewState State;
+        }
+    }
+}
+#endif
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