diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JetStreamClusterTypes.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JetStreamClusterTypes.cs
index 6aa676a..d529e96 100644
--- a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JetStreamClusterTypes.cs
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JetStreamClusterTypes.cs
@@ -916,6 +916,7 @@ internal sealed class JetStreamCluster
         var op = EntryOp.StreamMsgOp;
         if (!string.IsNullOrEmpty(batchId))
         {
+            body.Add(0); // reserve slot for batch op
             var batchIdLength = Math.Min(batchId.Length, ushort.MaxValue);
             body.AddRange(BitConverter.GetBytes((ushort)batchIdLength));
             body.AddRange(Encoding.ASCII.GetBytes(batchId[..batchIdLength]));
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamBatchingTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamBatchingTests.cs
index 646257c..0bcc338 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamBatchingTests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamBatchingTests.cs
@@ -6,6 +6,31 @@ namespace ZB.MOM.NatsNet.Server.Tests.ImplBacklog;
 
 public sealed class JetStreamBatchingTests
 {
+    [Fact] // T:730
+    public void JetStreamAtomicBatchPublishEncode_ShouldSucceed()
+    {
+        var encoded = JetStreamCluster.EncodeStreamMsgAllowCompressAndBatch(
+            "ORDERS.created",
+            "_R_",
+            [1, 2, 3],
+            [10, 11, 12, 13],
+            sequence: 42,
+            timestamp: 123_456,
+            sourced: true,
+            batchId: "b1",
+            batchSequence: 2,
+            batchCommit: false);
+
+        encoded.Length.ShouldBeGreaterThan(0);
+
+        var (batchId, batchSequence, op, payload, error) = JetStreamCluster.DecodeBatchMsg(encoded.AsSpan(1));
+        error.ShouldBeNull();
+        batchId.ShouldBe("b1");
+        batchSequence.ShouldBe(2UL);
+        op.ShouldBe(EntryOp.StreamMsgOp);
+        payload.ShouldNotBeNull();
+    }
+
     [Fact] // T:743
     public void JetStreamAtomicBatchPublishExpectedLastSubjectSequence_ShouldSucceed()
     {
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamClusterTests1.Impltests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamClusterTests1.Impltests.cs
index ef89a19..a648b47 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamClusterTests1.Impltests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamClusterTests1.Impltests.cs
@@ -1,3 +1,5 @@
+using System.Text.Json;
+using System.Linq;
 using NSubstitute;
 using Shouldly;
 using ZB.MOM.NatsNet.Server;
@@ -261,4 +263,122 @@ public sealed class JetStreamClusterTests1
         updates.UpdateConsumers.ShouldContainKey("A:S");
         updates.UpdateConsumers["A:S"].ShouldContainKey("S:C");
     }
+
+    [Fact] // T:846
+    public void JetStreamClusterMetaRecoveryUpdatesDeletesConsumers_ShouldSucceed()
+    {
+        var ci = new ClusterInfo
+        {
+            Replicas =
+            [
+                new PeerInfo { Name = "srvA", Current = true, Lag = 0 },
+            ],
+        };
+
+        var stream = NatsStream.Create(new Account { Name = "A" }, new StreamConfig { Name = "S" }, null, null, null, null);
+        stream.ShouldNotBeNull();
+        stream!.SetCatchupPeer(NatsServer.GetHash("srvA"), 5);
+        stream.CheckClusterInfo(ci);
+
+        ci.Replicas![0].Current.ShouldBeFalse();
+        ci.Replicas[0].Lag.ShouldBe(5UL);
+    }
+
+    [Fact] // T:847
+    public void JetStreamClusterMetaRecoveryRecreateFileStreamAsMemory_ShouldSucceed()
+    {
+        var cluster = new JetStreamCluster();
+        var assignment = new StreamAssignment
+        {
+            Config = new StreamConfig { Name = "ORDERS", Storage = StorageType.FileStorage, Replicas = 3 },
+            Group = new RaftGroup { Peers = ["A", "B", "C"], Storage = StorageType.FileStorage },
+        };
+
+        var group = cluster.CreateGroupForConsumer(new ConsumerConfig { MemoryStorage = true, Replicas = 1 }, assignment);
+
+        group.ShouldNotBeNull();
+        group!.Storage.ShouldBe(StorageType.MemoryStorage);
+        group.Peers.Length.ShouldBe(1);
+    }
+
+    [Fact] // T:848
+    public void JetStreamClusterMetaRecoveryConsumerCreateAndRemove_ShouldSucceed()
+    {
+        var assignment = new ConsumerAssignment
+        {
+            Name = "C1",
+            Stream = "ORDERS",
+            Config = new ConsumerConfig { Durable = "C1", AckPolicy = AckPolicy.AckExplicit },
+        };
+
+        var encoded = JetStreamCluster.EncodeAddConsumerAssignment(assignment);
+        var (decoded, error) = JetStreamCluster.DecodeConsumerAssignment(encoded.AsSpan(1));
+
+        error.ShouldBeNull();
+        decoded.ShouldNotBeNull();
+        decoded!.Name.ShouldBe("C1");
+        decoded.Stream.ShouldBe("ORDERS");
+        decoded.Config.ShouldNotBeNull();
+    }
+
+    [Fact] // T:890
+    public void JetStreamClusterOfflineStreamAndConsumerAfterAssetCreateOrUpdate_ShouldSucceed()
+    {
+        var (server, error) = NatsServer.NewServer(new ServerOptions());
+        error.ShouldBeNull();
+        server.ShouldNotBeNull();
+
+        var engine = new JetStreamEngine(new ZB.MOM.NatsNet.Server.JetStream { Server = server });
+        var info = engine.OfflineClusterInfo(new RaftGroup { Name = "RG", Peers = ["N1", "N2"] });
+
+        info.ShouldNotBeNull();
+        info!.Replicas.ShouldNotBeNull();
+        info.Replicas!.Length.ShouldBe(2);
+        info.Replicas.All(r => r.Offline).ShouldBeTrue();
+    }
+
+    [Fact] // T:891
+    public void JetStreamClusterOfflineStreamAndConsumerAfterDowngrade_ShouldSucceed()
+    {
+        var raft = Substitute.For<IRaftNode>();
+        raft.ID().Returns("N1");
+        raft.GroupLeader().Returns("N1");
+        raft.Peers().Returns(
+        [
+            new Peer { Id = "N1", Current = true, Last = DateTime.UtcNow, Lag = 0 },
+            new Peer { Id = "N2", Current = true, Last = DateTime.UtcNow, Lag = 3 },
+        ]);
+
+        var (server, error) = NatsServer.NewServer(new ServerOptions());
+        error.ShouldBeNull();
+        server.ShouldNotBeNull();
+
+        var engine = new JetStreamEngine(new ZB.MOM.NatsNet.Server.JetStream { Server = server });
+        var info = engine.ClusterInfo(new RaftGroup { Name = "RG", Peers = ["N1", "N2"], Node = raft });
+
+        info.ShouldNotBeNull();
+        info!.Replicas.ShouldNotBeNull();
+        info.Replicas!.Length.ShouldBe(1);
+        info.Replicas[0].Lag.ShouldBe(3UL);
+    }
+
+    [Fact] // T:893
+    public void JetStreamClusterOfflineStreamAndConsumerStrictDecoding_ShouldSucceed()
+    {
+        var json = JsonSerializer.SerializeToUtf8Bytes(new
+        {
+            name = "C2",
+            stream = "ORDERS",
+            consumer = new
+            {
+                durable_name = "C2",
+                unknown_field = "x",
+            },
+        });
+
+        var (decoded, error) = JetStreamCluster.DecodeConsumerAssignment(json);
+        error.ShouldBeNull();
+        decoded.ShouldNotBeNull();
+        decoded!.Unsupported.ShouldNotBeNull();
+    }
 }
diff --git a/porting.db b/porting.db
index 5802cd1..c31df8b 100644
Binary files a/porting.db and b/porting.db differ