Microsoft.AspNetCore.SignalR.Protocols.Json

 {
     namespace Microsoft.AspNetCore.SignalR {
         public class JsonHubProtocolOptions {
+            public JsonSerializerOptions PayloadSerializerOptions { get; set; }
-            public JsonSerializerSettings PayloadSerializerSettings { get; set; }

         }
     }
     namespace Microsoft.AspNetCore.SignalR.Protocol {
-        public class JsonHubProtocol : IHubProtocol {
+        public sealed class JsonHubProtocol : IHubProtocol {
-            public JsonSerializer PayloadSerializer { get; }

         }
     }
 }