I've never been able to get a certain answer, but I assume they're going to be asking localities to allow them to have their new 8500s and NEXTs on county systems.
They're no longer installing SIRS radios in the newest explorers. SIRS is still pretty heavily relied on by agencies out west to get in contact with the trooper working their county.
So it's my assumption with that info that they will be making that move at some point. Especially given how much easier it is to make programming changes OTA with the NEXTs. No reason to get multiband radios if you're not going to use them with all bands.