diff --git a/ably.d.ts b/ably.d.ts
index be483f1c5..228f90b78 100644
--- a/ably.d.ts
+++ b/ably.d.ts
@@ -2332,6 +2332,7 @@ export interface Message {
   name?: string;
   /**
    * Timestamp of when the message was received by Ably, as milliseconds since the Unix epoch.
+   * (This is the timestamp of the current version of the message)
    */
   timestamp?: number;
   /**
@@ -2339,27 +2340,32 @@ export interface Message {
    */
   action?: MessageAction;
   /**
-   * This message's unique serial.
+   * This message's unique serial (an identifier that will be the same in all future
+   * updates of this message).
    */
   serial?: string;
   /**
-   * The serial of the message that this message is a reference to.
+   * If this message references another, the serial of that message.
    */
   refSerial?: string;
   /**
-   * The type of reference this message is, in relation to the message it references.
+   * If this message references another, the type of reference that is.
    */
   refType?: string;
   /**
-   * If an `update` operation was applied to this message, this will be the timestamp the update occurred.
+   * The timestamp of the very first version of a given message (will differ from
+   * createdAt only if the message has been updated or deleted).
    */
-  updatedAt?: number;
+  createdAt?: number;
   /**
-   * The serial of the operation that updated this message.
+   * The version of the message, lexicographically-comparable with other versions (that
+   * share the same serial) Will differ from the serial only if the message has been
+   * updated or deleted.
    */
-  updateSerial?: string;
+  version?: string;
   /**
-   * If this message resulted from an operation, this will contain the operation details.
+   * In the case of an updated or deleted message, this will contain metadata about the
+   * update or delete operation.
    */
   operation?: Operation;
 }
diff --git a/src/common/lib/client/realtimechannel.ts b/src/common/lib/client/realtimechannel.ts
index 24ffe62cf..dad5eede3 100644
--- a/src/common/lib/client/realtimechannel.ts
+++ b/src/common/lib/client/realtimechannel.ts
@@ -622,6 +622,7 @@ class RealtimeChannel extends EventEmitter {
           firstMessage = messages[0],
           lastMessage = messages[messages.length - 1],
           id = message.id,
+          channelSerial = message.channelSerial,
           connectionId = message.connectionId,
           timestamp = message.timestamp;
 
@@ -670,9 +671,14 @@ class RealtimeChannel extends EventEmitter {
           if (!msg.connectionId) msg.connectionId = connectionId;
           if (!msg.timestamp) msg.timestamp = timestamp;
           if (!msg.id) msg.id = id + ':' + i;
+          if (!msg.version) msg.version = channelSerial + ':' + i.toString().padStart(3, '0');
+
+          // already done in fromWireProtocol -- but for realtime messages the source
+          // fields might be copied from the protocolmessage, so need to do it again
+          msg.expandFields();
         }
         this._lastPayload.messageId = lastMessage.id;
-        this._lastPayload.protocolMessageChannelSerial = message.channelSerial;
+        this._lastPayload.protocolMessageChannelSerial = channelSerial;
         this.onEvent(messages);
         break;
       }
diff --git a/src/common/lib/types/message.ts b/src/common/lib/types/message.ts
index 3e522c7b2..ebaddbe1c 100644
--- a/src/common/lib/types/message.ts
+++ b/src/common/lib/types/message.ts
@@ -281,7 +281,9 @@ export function fromValues(values: Properties<Message>): Message {
 
 export function fromWireProtocol(values: WireProtocolMessage): Message {
   const action = toMessageActionString(values.action as number) || values.action;
-  return Object.assign(new Message(), { ...values, action });
+  const res = Object.assign(new Message(), { ...values, action });
+  res.expandFields();
+  return res;
 }
 
 export function fromValuesArray(values: Properties<Message>[]): Message[] {
@@ -315,8 +317,8 @@ class Message {
   serial?: string;
   refSerial?: string;
   refType?: string;
-  updatedAt?: number;
-  updateSerial?: string;
+  createdAt?: number;
+  version?: string;
   operation?: API.Operation;
 
   /**
@@ -352,14 +354,27 @@ class Message {
       action: toMessageActionNumber(this.action as API.MessageAction) || this.action,
       refSerial: this.refSerial,
       refType: this.refType,
-      updatedAt: this.updatedAt,
-      updateSerial: this.updateSerial,
+      createdAt: this.createdAt,
+      version: this.version,
       operation: this.operation,
       encoding,
       data,
     };
   }
 
+  expandFields() {
+    if (this.action === 'message.create') {
+      // TM2k
+      if (this.version && !this.serial) {
+        this.serial = this.version;
+      }
+      // TM2o
+      if (this.timestamp && !this.createdAt) {
+        this.createdAt = this.timestamp;
+      }
+    }
+  }
+
   toString(): string {
     let result = '[Message';
     if (this.name) result += '; name=' + this.name;
@@ -379,10 +394,10 @@ class Message {
 
     if (this.action) result += '; action=' + this.action;
     if (this.serial) result += '; serial=' + this.serial;
+    if (this.version) result += '; version=' + this.version;
     if (this.refSerial) result += '; refSerial=' + this.refSerial;
     if (this.refType) result += '; refType=' + this.refType;
-    if (this.updatedAt) result += '; updatedAt=' + this.updatedAt;
-    if (this.updateSerial) result += '; updateSerial=' + this.updateSerial;
+    if (this.createdAt) result += '; createdAt=' + this.createdAt;
     if (this.operation) result += '; operation=' + JSON.stringify(this.operation);
     result += ']';
     return result;
diff --git a/test/realtime/message.test.js b/test/realtime/message.test.js
index 1490bdd7b..9f54cce7d 100644
--- a/test/realtime/message.test.js
+++ b/test/realtime/message.test.js
@@ -1310,6 +1310,25 @@ define(['ably', 'shared_helper', 'async', 'chai'], function (Ably, Helper, async
           expect(message.toJSON()).to.deep.contains(expectedJSON);
         });
       });
+
+      /**
+       * @spec TM2k
+       * @spec TM2o
+       */
+      it('create message should fill out serial and createdAt from version/timestamp', function () {
+        const values = { action: 1, timestamp: 12345, version: 'foo' };
+        const message = Message.fromWireProtocol(values);
+        expect(message.timestamp).to.equal(12345);
+        expect(message.createdAt).to.equal(12345);
+        expect(message.version).to.equal('foo');
+        expect(message.serial).to.equal('foo');
+
+        // should only apply to creates
+        const update = { action: 2, timestamp: 12345, version: 'foo' };
+        const updateMessage = Message.fromWireProtocol(update);
+        expect(updateMessage.createdAt).to.equal(undefined);
+        expect(updateMessage.serial).to.equal(undefined);
+      });
     });
 
     /**