diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamEngineTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamEngineTests.cs
index b804991..26f073f 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamEngineTests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamEngineTests.cs
@@ -6,6 +6,71 @@ namespace ZB.MOM.NatsNet.Server.Tests.ImplBacklog;
 
 public sealed class JetStreamEngineTests
 {
+    [Fact] // T:1716
+    public void IsJSONObjectOrArray_ShouldSucceed()
+    {
+        var tests = new (string Name, byte[] Data, bool Valid)[]
+        {
+            ("empty", [], false),
+            ("empty_object", "{}"u8.ToArray(), true),
+            ("empty object, not trimmed", "\t\n\r{ }"u8.ToArray(), true),
+            ("empty_array", "[]"u8.ToArray(), true),
+            ("empty array, not trimmed", "\t\n\r[ ]"u8.ToArray(), true),
+            ("empty_string", "\"\""u8.ToArray(), false),
+            ("whitespace_only", "   "u8.ToArray(), false),
+            ("object_with_whitespace", "{   }"u8.ToArray(), true),
+            ("array_with_whitespace", "[   ]"u8.ToArray(), true),
+            ("string_with_whitespace", "   \"text\""u8.ToArray(), false),
+            ("number", "123"u8.ToArray(), false),
+            ("boolean_true", "true"u8.ToArray(), false),
+            ("boolean_false", "false"u8.ToArray(), false),
+            ("null_value", "null"u8.ToArray(), false),
+            ("invalid_json", "invalid"u8.ToArray(), false),
+        };
+
+        foreach (var test in tests)
+        {
+            JetStreamApi.IsJSONObjectOrArray(test.Data).ShouldBe(test.Valid, test.Name);
+        }
+    }
+
+    [Fact] // T:1719
+    public void JetStreamDelayedAPIResponses_ShouldSucceed()
+    {
+        var account = new Account { Name = "ACC" };
+        DelayedApiResponse? head = null;
+        DelayedApiResponse? tail = null;
+        var now = DateTime.UtcNow;
+
+        var responses = new[]
+        {
+            NewDelayed(account, "request2", "response2", now.AddMilliseconds(500)),
+            NewDelayed(account, "request1", "response1", now.AddMilliseconds(200)),
+            NewDelayed(account, "request4", "response4", now.AddMilliseconds(800)),
+            NewDelayed(account, "request3", "response3", now.AddMilliseconds(650)),
+        };
+
+        foreach (var response in responses)
+            JetStreamApi.AddDelayedResponse(ref head, ref tail, response);
+
+        var orderedRequests = new List<string>();
+        for (var current = head; current is not null; current = current.Next)
+            orderedRequests.Add(current.Request);
+
+        orderedRequests.ShouldBe(["request1", "request2", "request3", "request4"]);
+    }
+
+    private static DelayedApiResponse NewDelayed(Account account, string request, string response, DateTime deadlineUtc) =>
+        new()
+        {
+            Account = account,
+            Subject = "SUB",
+            Reply = string.Empty,
+            Request = request,
+            Response = response,
+            DeadlineUtc = deadlineUtc,
+        };
+
     [Fact] // T:1477
     public void JetStreamMaxConsumers_ShouldSucceed()
     {
diff --git a/porting.db b/porting.db
index 1e4d39e..7ec2d0e 100644
Binary files a/porting.db and b/porting.db differ