diff --git a/osu.Game.Tests/Chat/TestSceneChannelManager.cs b/osu.Game.Tests/Chat/TestSceneChannelManager.cs
index 86be638781..f559b0db73 100644
--- a/osu.Game.Tests/Chat/TestSceneChannelManager.cs
+++ b/osu.Game.Tests/Chat/TestSceneChannelManager.cs
@@ -23,6 +23,7 @@ namespace osu.Game.Tests.Chat
         private ChannelManager channelManager;
         private int currentMessageId;
         private List<Message> sentMessages;
+        private List<int> silencedUserIds;
 
         [SetUp]
         public void Setup() => Schedule(() =>
@@ -39,6 +40,7 @@ namespace osu.Game.Tests.Chat
             {
                 currentMessageId = 0;
                 sentMessages = new List<Message>();
+                silencedUserIds = new List<int>();
 
                 ((DummyAPIAccess)API).HandleRequest = req =>
                 {
@@ -55,6 +57,11 @@ namespace osu.Game.Tests.Chat
                         case MarkChannelAsReadRequest markRead:
                             handleMarkChannelAsReadRequest(markRead);
                             return true;
+
+                        case ChatAckRequest ack:
+                            ack.TriggerSuccess(new ChatAckResponse { Silences = silencedUserIds.Select(u => new ChatSilence { UserId = u }).ToList() });
+                            silencedUserIds.Clear();
+                            return true;
                     }
 
                     return false;
@@ -106,6 +113,28 @@ namespace osu.Game.Tests.Chat
             AddAssert("channel's last read ID is set to the latest message", () => channel.LastReadId == sentMessages.Last().Id);
         }
 
+        [Test]
+        public void TestSilencedUsersAreRemoved()
+        {
+            Channel channel = null;
+
+            AddStep("join channel and select it", () =>
+            {
+                channelManager.JoinChannel(channel = createChannel(1, ChannelType.Public));
+                channelManager.CurrentChannel.Value = channel;
+            });
+
+            AddStep("post message", () => channelManager.PostMessage("Definitely something bad"));
+
+            AddStep("mark user as silenced and send ack request", () =>
+            {
+                silencedUserIds.Add(API.LocalUser.Value.OnlineID);
+                channelManager.SendAck();
+            });
+
+            AddAssert("channel has no more messages", () => channel.Messages, () => Is.Empty);
+        }
+
         private void handlePostMessageRequest(PostMessageRequest request)
         {
             var message = new Message(++currentMessageId)
diff --git a/osu.Game/Online/API/Requests/ChatAckRequest.cs b/osu.Game/Online/API/Requests/ChatAckRequest.cs
index f09df4908e..78f51e21c0 100644
--- a/osu.Game/Online/API/Requests/ChatAckRequest.cs
+++ b/osu.Game/Online/API/Requests/ChatAckRequest.cs
@@ -9,10 +9,16 @@ namespace osu.Game.Online.API.Requests
 {
     public class ChatAckRequest : APIRequest<ChatAckResponse>
     {
+        public long SinceMessageId;
+        public uint? SinceSilenceId;
+
         protected override WebRequest CreateWebRequest()
         {
             var req = base.CreateWebRequest();
             req.Method = HttpMethod.Post;
+            req.AddParameter(@"since", SinceMessageId.ToString());
+            if (SinceSilenceId != null)
+                req.AddParameter(@"history_since", SinceSilenceId.Value.ToString());
             return req;
         }
 
diff --git a/osu.Game/Online/API/Requests/Responses/ChatSilence.cs b/osu.Game/Online/API/Requests/Responses/ChatSilence.cs
index 45fd6e1ba3..afb44e385e 100644
--- a/osu.Game/Online/API/Requests/Responses/ChatSilence.cs
+++ b/osu.Game/Online/API/Requests/Responses/ChatSilence.cs
@@ -12,6 +12,6 @@ namespace osu.Game.Online.API.Requests.Responses
         public uint Id { get; set; }
 
         [JsonProperty("user_id")]
-        public uint UserId { get; set; }
+        public int UserId { get; set; }
     }
 }
diff --git a/osu.Game/Online/Chat/ChannelManager.cs b/osu.Game/Online/Chat/ChannelManager.cs
index a901c15bf4..b9a0aacf5a 100644
--- a/osu.Game/Online/Chat/ChannelManager.cs
+++ b/osu.Game/Online/Chat/ChannelManager.cs
@@ -74,6 +74,9 @@ namespace osu.Game.Online.Chat
         private bool channelsInitialised;
         private ScheduledDelegate ackDelegate;
 
+        private long lastMessageId;
+        private uint? lastSilenceId;
+
         public ChannelManager(IAPIProvider api, NotificationsClientConnector connector)
         {
             this.api = api;
@@ -106,8 +109,7 @@ namespace osu.Game.Online.Chat
 
                 if (status.NewValue == APIState.Online)
                 {
-                    Scheduler.Add(ackDelegate = new ScheduledDelegate(() => api.Queue(new ChatAckRequest()), 0, 60000));
-                    // Todo: Handle silences.
+                    Scheduler.Add(ackDelegate = new ScheduledDelegate(SendAck, 0, 60000));
                 }
             }, true);
         }
@@ -342,6 +344,8 @@ namespace osu.Game.Online.Chat
 
             foreach (var group in messages.GroupBy(m => m.ChannelId))
                 channels.Find(c => c.Id == group.Key)?.AddNewMessages(group.ToArray());
+
+            lastMessageId = messages.LastOrDefault()?.Id ?? lastMessageId;
         }
 
         private void initializeChannels()
@@ -391,6 +395,32 @@ namespace osu.Game.Online.Chat
             api.Queue(fetchInitialMsgReq);
         }
 
+        /// <summary>
+        /// Sends an acknowledgement request to the API.
+        /// This marks the user as online to receive messages from public channels, while also returning a list of silenced users.
+        /// It needs to be called at least once every 10 minutes.
+        /// </summary>
+        public void SendAck()
+        {
+            var req = new ChatAckRequest
+            {
+                SinceMessageId = lastMessageId,
+                SinceSilenceId = lastSilenceId
+            };
+
+            req.Success += ack =>
+            {
+                foreach (var silence in ack.Silences)
+                {
+                    foreach (var channel in JoinedChannels)
+                        channel.RemoveMessagesFromUser(silence.UserId);
+                    lastSilenceId = Math.Max(lastSilenceId ?? 0, silence.Id);
+                }
+            };
+
+            api.Queue(req);
+        }
+
         /// <summary>
         /// Find an existing channel instance for the provided channel. Lookup is performed basd on ID.
         /// The provided channel may be used if an existing instance is not found.