Yep "Iridium NEXT will maintain the architecture of our current...

Yep

"Iridium NEXT will maintain the architecture of our current constellation, with 66 in-orbit satellites, as well as six in-orbit spares, and we are building nine ground spares. We have contracted with Thales Alenia Space France, or Thales, to construct the Iridium NEXT satellites, which are designed to be compatible with our current constellation and current end-user equipment, so that as the Iridium NEXT satellites are launched, they will replace satellites in the current constellation without affecting the service to our end users"

Read more: http://www.getfilings.com/sec-filings/150226/Iridium-Communications-Inc_10-K/#ixzz3TnIo6CBP