diff --git a/osu.Game/Online/Spectator/SpectatorStreamingClient.cs b/osu.Game/Online/Spectator/SpectatorStreamingClient.cs
index d93de3a710..a89cc82535 100644
--- a/osu.Game/Online/Spectator/SpectatorStreamingClient.cs
+++ b/osu.Game/Online/Spectator/SpectatorStreamingClient.cs
@@ -4,6 +4,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.SignalR.Client;
 using Microsoft.Extensions.DependencyInjection;
+using Newtonsoft.Json;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -75,7 +76,7 @@ namespace osu.Game.Online.Spectator
                          {
                              options.Headers.Add("Authorization", $"Bearer {api.AccessToken}");
                          })
-                         .AddMessagePackProtocol()
+                         .AddNewtonsoftJsonProtocol(options => { options.PayloadSerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore; })
                          .Build();
 
             // until strong typed client support is added, each method must be manually bound (see https://github.com/dotnet/aspnetcore/issues/15198)
@@ -147,11 +148,15 @@ namespace osu.Game.Online.Spectator
             return Task.CompletedTask;
         }
 
-        public void BeginPlaying(int beatmapId)
+        public void BeginPlaying()
         {
             if (!isConnected) return;
 
-            connection.SendAsync(nameof(ISpectatorServer.BeginPlaySession), beatmapId);
+            // transfer state at point of beginning play
+            currentState.BeatmapID = beatmap.Value.BeatmapInfo.OnlineBeatmapID;
+            currentState.Mods = mods.Value.ToArray();
+
+            connection.SendAsync(nameof(ISpectatorServer.BeginPlaySession), currentState);
         }
 
         public void SendFrames(FrameDataBundle data)
diff --git a/osu.Game/Replays/Legacy/LegacyReplayFrame.cs b/osu.Game/Replays/Legacy/LegacyReplayFrame.cs
index 656fd1814e..c3cffa8699 100644
--- a/osu.Game/Replays/Legacy/LegacyReplayFrame.cs
+++ b/osu.Game/Replays/Legacy/LegacyReplayFrame.cs
@@ -1,7 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using MessagePack;
 using osu.Game.Rulesets.Replays;
 using osuTK;
 
@@ -9,7 +8,6 @@ namespace osu.Game.Replays.Legacy
 {
     public class LegacyReplayFrame : ReplayFrame
     {
-        [IgnoreMember]
         public Vector2 Position => new Vector2(MouseX ?? 0, MouseY ?? 0);
 
         public float? MouseX;
diff --git a/osu.Game/osu.Game.csproj b/osu.Game/osu.Game.csproj
index fd010fcc43..ca588b89d9 100644
--- a/osu.Game/osu.Game.csproj
+++ b/osu.Game/osu.Game.csproj
@@ -21,9 +21,8 @@
     <PackageReference Include="Dapper" Version="2.0.35" />
     <PackageReference Include="DiffPlex" Version="1.6.3" />
     <PackageReference Include="Humanizer" Version="2.8.26" />
-    <PackageReference Include="MessagePack" Version="1.7.3.7" />
     <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="3.1.9" />
-    <PackageReference Include="Microsoft.AspNetCore.SignalR.Protocols.MessagePack" Version="3.1.9" />
+    <PackageReference Include="Microsoft.AspNetCore.SignalR.Protocols.NewtonsoftJson" Version="3.1.9" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.2.6" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite.Core" Version="2.2.6" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />