@dpl73 

do a backup of old controller, then restore to new. turn off the old controller.

change ip on new controller same as the old one or use omada discovery utility on remote site and point to the ip on new controller

You can also use DHCP option 138 on remote site to point to ip on controller

then everything should work :-)

  @shberge 

Thanks.  I'm using option 138.  However, I havn't broached the remote sites yet as the local is a bigger problem ;-/  If I can't get the switches migrated relatively seamlessly, then I'm going to have to have a rethink.  The 10g ports on the switches provide SAN traffic to a local esxi cluster.  If they go down, everything does ;-)

  @dpl73 

if everything is on same LAN do restore to new controller and then power off oc200, then device will then automatic find the new controller and adopt automatic. you dont ned to do anything,

then remote site need to know the ip on new controller, easiest is to give the new controller same ip as the old one. then remotedevice adopt automatic to new controller to.

  @shberge 

Thanks again! Maybe I'm not giving it long enough for discovery (10-15 mins)  I'll pick this up again tomorrow and give it a decent amount of time for the clients to find the controller. 

  @dpl73 

another option is Controller Migration, I have not tested this myself I always use backup and restore and it always work,

but I think Controller Migration have option to set ip on new controller. 

but you dont need to forgett device and adopt again, if you do that you los device configuration.