I don't know of any airline that will email you for an equipment change (unless it results in the deletion of the cabin you are in, eg 4-cabin subbed for a 3-cabin). Use Expertflyer to set an alert for that.
Same thing happened to my flight for tomorrow. But contrary to the comments above, it's not the same at all. The 787 is a different aircraft with different amenities other than the cabin class. If they were the same than the 333 would have the same power options in PE and E as the 787, the Wander Wall, etc.