The refresh button was removed to make way for a more intuitive "Pull-to-refresh" option. Just pull down on your schedule and then let go. That will trigger the refresh process with the pop-up and loading bar.
This change was implemented to clean up the Title Bar and to allow Apple users to refresh from both the Calendar and Daily pages. If you don't like the new refresh method, you can still use the refresh button. You can find it in the menu.