You could never play a course, but you had the ability to replay an activity on the Player page. It looks like this player functionality is now on the activity details page. There is a play button on the map (bottom center), and you can now click and zoom in on the graphs to inspect the data at each point.
My fault.I mean activity.I have see the play button but In previous version i could "play" the activity step step,now i can not find the way (if there is any).
There are no longer buttons to advance/retreat the playback by some set time interval. Instead, just move your mouse over the graph. The indicator on the map will move as you move the mouse over the data. Previously, the map didn't update until you clicked on on the graph.