One of these days they will orchestrate suicide bombers like a controlled explosion map, each bomber has a gps unit that detonates automatically when in a predetermined position and time. More than likely a simple app like facebook would work.
My bigger fear is something like the Russian jetliner blown up by a soda can bomb.
If they are mass-produced and convincingly sealed, and each includes a digital date-time watch detonator, any number of jihadists could just be told, “Be in an airplane or someplace crowded on the 4th of July at noon GMT” or whenever they are set to all explode.
My guess is the plane brought down over the Med was also a victim of a soda-can bomb.