diff --git a/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/README.txt b/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/README.txt
new file mode 100644
index 0000000000..0b46df9df6
--- /dev/null
+++ b/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/README.txt
@@ -0,0 +1,29 @@
+SimpleJson is from https://github.com/facebook-csharp-sdk/simple-json
+
+CHANGES MADE
+============
+* Better handling of System.DateTime serialized by Json.NET
+  as suggested in https://github.com/facebook-csharp-sdk/simple-json/issues/78
+
+LICENSE (from https://github.com/facebook-csharp-sdk/simple-json/blob/08b6871e8f63e866810d25e7a03c48502c9a234b/LICENSE.txt):
+=====
+Copyright (c) 2011, The Outercurve Foundation
+
+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.
\ No newline at end of file
diff --git a/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/SimpleJson.cs b/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/SimpleJson.cs
index b20d8661d0..33fa6088ce 100644
--- a/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/SimpleJson.cs
+++ b/src/Microsoft.AspNetCore.Blazor/Json/SimpleJson/SimpleJson.cs
@@ -1343,7 +1343,8 @@ namespace SimpleJson
                 if (str.Length != 0) // We know it can't be null now.
                 {
                     if (type == typeof(DateTime) || (ReflectionUtils.IsNullableType(type) && Nullable.GetUnderlyingType(type) == typeof(DateTime)))
-                        return DateTime.ParseExact(str, Iso8601Format, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
+                        return DateTime.TryParseExact(str, Iso8601Format, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal, out var result)
+                            ? result : DateTime.Parse(str, CultureInfo.InvariantCulture, DateTimeStyles.RoundtripKind);
                     if (type == typeof(DateTimeOffset) || (ReflectionUtils.IsNullableType(type) && Nullable.GetUnderlyingType(type) == typeof(DateTimeOffset)))
                         return DateTimeOffset.ParseExact(str, Iso8601Format, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal);
                     if (type == typeof(Guid) || (ReflectionUtils.IsNullableType(type) && Nullable.GetUnderlyingType(type) == typeof(Guid)))