I just got some further clarification. Modesto PD (MPD) has transitioned fully to the trunked system. They are leaving the old UHF dispatch channel active for now. Previously, Sheriff's Office patrol monitored MPD via scanner on their UHF dispatch channel. Since that won't be around much longer, dispatch has patched MPD traffic to the county interop 151.115 so they can continue monitoring them.
Fire agencies, Ceres and Turlock still have a way to go is my understanding. Talkgroups have been assigned to those agencies however, so their transition is still the plan.