No template changes have been made, however, there are two template options that are available.  You can check to see which template options have been assigned to both your new event and your existing events by following the instructions below:
  1. Content>Events
  2. Click Edit next to the appropriate event
  3. From step 1, go to option 4 -  Registration Page Template
  4. Verify whether the event has been set to Standard or Custom
  5. If necessary, mark the appropriate template followed by clicking Next (any changes will be saved)