diff --git a/src/channel.ts b/src/channel.ts
index 16cab802a..2812c2fff 100644
--- a/src/channel.ts
+++ b/src/channel.ts
@@ -1241,7 +1241,6 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
       case 'message.read':
         if (event.user?.id && event.created_at) {
           channelState.read[event.user.id] = {
-            // because in client.ts the handleEvent call that flows to this sets this `event.received_at = new Date();`
             last_read: new Date(event.created_at),
             last_read_message_id: event.last_read_message_id,
             user: event.user,
@@ -1360,6 +1359,21 @@ export class Channel<StreamChatGenerics extends ExtendableGenerics = DefaultGene
           delete channelState.members[event.user.id];
         }
         break;
+      case 'notification.mark_unread': {
+        const ownMessage = event.user?.id === this.getClient().user?.id;
+        if (!(ownMessage && event.user)) break;
+
+        channelState.read[event.user.id] = {
+          first_unread_message_id: event.first_unread_message_id,
+          last_read: new Date(event.last_read_at as string),
+          last_read_message_id: event.last_read_message_id,
+          user: event.user,
+          unread_messages: event.unread_messages ?? 0,
+        };
+
+        channelState.unreadCount = event.unread_messages ?? 0;
+        break;
+      }
       case 'channel.updated':
         if (event.channel) {
           const isFrozenChanged = event.channel?.frozen !== undefined && event.channel.frozen !== channel.data?.frozen;
diff --git a/src/channel_state.ts b/src/channel_state.ts
index 2cfb1a95f..66b93fbac 100644
--- a/src/channel_state.ts
+++ b/src/channel_state.ts
@@ -15,7 +15,13 @@ import {
 
 type ChannelReadStatus<StreamChatGenerics extends ExtendableGenerics = DefaultGenerics> = Record<
   string,
-  { last_read: Date; unread_messages: number; user: UserResponse<StreamChatGenerics>; last_read_message_id?: string }
+  {
+    last_read: Date;
+    unread_messages: number;
+    user: UserResponse<StreamChatGenerics>;
+    first_unread_message_id?: string;
+    last_read_message_id?: string;
+  }
 >;
 
 /**
diff --git a/src/events.ts b/src/events.ts
index 74e984210..25f378b2c 100644
--- a/src/events.ts
+++ b/src/events.ts
@@ -24,6 +24,7 @@ export const EVENT_MAP = {
   'notification.invite_rejected': true,
   'notification.invited': true,
   'notification.mark_read': true,
+  'notification.mark_unread': true,
   'notification.message_new': true,
   'notification.mutes_updated': true,
   'notification.removed_from_channel': true,
diff --git a/src/types.ts b/src/types.ts
index 96139b5d8..9aefd6235 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1055,8 +1055,13 @@ export type Event<StreamChatGenerics extends ExtendableGenerics = DefaultGeneric
   cid?: string;
   clear_history?: boolean;
   connection_id?: string;
+  // event creation timestamp, format Date ISO string
   created_at?: string;
+  // id of the message that was marked as unread - all the following messages are considered unread. (notification.mark_unread)
+  first_unread_message_id?: string;
   hard_delete?: boolean;
+  // creation date of a message with last_read_message_id, formatted as Date ISO string
+  last_read_at?: string;
   last_read_message_id?: string;
   mark_messages_deleted?: boolean;
   me?: OwnUserResponse<StreamChatGenerics>;
@@ -1072,9 +1077,14 @@ export type Event<StreamChatGenerics extends ExtendableGenerics = DefaultGeneric
   reaction?: ReactionResponse<StreamChatGenerics>;
   received_at?: string | Date;
   team?: string;
+  // @deprecated number of all unread messages across all current user's unread channels, equals unread_count
   total_unread_count?: number;
+  // number of all current user's channels with at least one unread message including the channel in this event
   unread_channels?: number;
+  // number of all unread messages across all current user's unread channels
   unread_count?: number;
+  // number of unread messages in the channel from this event (notification.mark_unread)
+  unread_messages?: number;
   user?: UserResponse<StreamChatGenerics>;
   user_id?: string;
   watcher_count?: number;
diff --git a/test/unit/channel.js b/test/unit/channel.js
index 0c7f49ab7..a95ad7d09 100644
--- a/test/unit/channel.js
+++ b/test/unit/channel.js
@@ -10,9 +10,7 @@ import { getOrCreateChannelApi } from './test-utils/getOrCreateChannelApi';
 import sinon from 'sinon';
 import { mockChannelQueryResponse } from './test-utils/mockChannelQueryResponse';
 
-import { StreamChat } from '../../src/client';
-import { ChannelState } from '../../src';
-import exp from 'constants';
+import { ChannelState, StreamChat } from '../../src';
 
 const expect = chai.expect;
 
@@ -353,6 +351,72 @@ describe('Channel _handleChannelEvent', function () {
 		expect(channel.state.messages.find((msg) => msg.id === quotingMessage.id).quoted_message.deleted_at).to.be.ok;
 	});
 
+	describe('notification.mark_unread', () => {
+		let initialCountUnread;
+		let initialReadState;
+		let notificationMarkUnreadEvent;
+		beforeEach(() => {
+			initialCountUnread = 0;
+			initialReadState = {
+				last_read: new Date().toISOString(),
+				last_read_message_id: '6',
+				user,
+				unread_messages: initialCountUnread,
+			};
+			notificationMarkUnreadEvent = {
+				type: 'notification.mark_unread',
+				created_at: new Date().toISOString(),
+				cid: channel.cid,
+				channel_id: channel.id,
+				channel_type: channel.type,
+				channel: null,
+				user,
+				first_unread_message_id: '2',
+				last_read_at: new Date(new Date(initialReadState.last_read).getTime() - 1000).toISOString(),
+				last_read_message_id: '1',
+				unread_messages: 5,
+				unread_count: 6,
+				total_unread_count: 6,
+				unread_channels: 2,
+			};
+		});
+
+		it('should update channel read state produced for current user', () => {
+			channel.state.unreadCount = initialCountUnread;
+			channel.state.read[user.id] = initialReadState;
+			const event = notificationMarkUnreadEvent;
+
+			channel._handleChannelEvent(event);
+
+			expect(channel.state.unreadCount).to.be.equal(event.unread_messages);
+			expect(new Date(channel.state.read[user.id].last_read).getTime()).to.be.equal(
+				new Date(event.last_read_at).getTime(),
+			);
+			expect(channel.state.read[user.id].last_read_message_id).to.be.equal(event.last_read_message_id);
+			expect(channel.state.read[user.id].unread_messages).to.be.equal(event.unread_messages);
+		});
+
+		it('should not update channel read state produced for another user or user is missing', () => {
+			channel.state.unreadCount = initialCountUnread;
+			channel.state.read[user.id] = initialReadState;
+			const { user: excludedUser, ...eventMissingUser } = notificationMarkUnreadEvent;
+			const eventWithAnotherUser = { ...notificationMarkUnreadEvent, user: { id: 'another-user' } };
+
+			[eventWithAnotherUser, eventMissingUser].forEach((event) => {
+				channel._handleChannelEvent(event);
+
+				expect(channel.state.unreadCount).to.be.equal(initialCountUnread);
+				expect(new Date(channel.state.read[user.id].last_read).getTime()).to.be.equal(
+					new Date(initialReadState.last_read).getTime(),
+				);
+				expect(channel.state.read[user.id].last_read_message_id).to.be.equal(
+					initialReadState.last_read_message_id,
+				);
+				expect(channel.state.read[user.id].unread_messages).to.be.equal(initialReadState.unread_messages);
+			});
+		});
+	});
+
 	it('should include unread_messages for message events from another user', () => {
 		channel.state.read['id'] = {
 			unread_messages: 2,
@@ -501,8 +565,7 @@ describe('Channel _handleChannelEvent', function () {
 
 	it(`should make sure that state reload doesn't wipe out existing data`, async () => {
 		const mock = sinon.mock(client);
-		const response = mockChannelQueryResponse;
-		mock.expects('post').returns(Promise.resolve(response));
+		mock.expects('post').returns(Promise.resolve(mockChannelQueryResponse));
 
 		channel.state.members = {
 			user: { id: 'user' },