Just got this from Delta! (
link to Delta this info is from)
Stopovers
For Award Travel booked prior to January 1, 2015, one stopover is allowed per roundtrip Award Ticket under certain circumstances. A stopover is defined as a stay of more than 4 hours between domestic flights and more than 24 hours between domestic and international or all international flights. The destination city is not considered a stopover. A stopover is allowed, provided there are no more than two connections between the origin and destination including any connections that are made while traveling to/from the stopover point. The stopover city must be located on a valid routing.
Stopovers will no longer be permitted for Award Travel booked on or after January 1, 2015.
Open Jaw
Open jaw Award Travel is permitted for Awards booked prior to January 1, 2015. To be eligible, the mileage between the open jaw points must be less than or equal to the total mileage flown between any other trip in the itinerary (origin to destination). A double open jaw is not permitted.
For Award Travel ticketed on or after January 1, 2015, all open jaw itineraries will be priced based on One-way Award Travel pricing rules.
http://deltapoints.boardingarea.com/...-skymiles2015/