@drgonzoo 

If memory serves me correctly, i was able to change the IP on the controller without hassle

@Philbert 

yes you can change the IP of the Controller, my problem ist that the offsite devices cant report to the Controller anymore afterwards. at least without resetting and re-adopting.

@drgonzoo 

Ah ok.. never tried this with an offsite AP, only ever been local / native

@drgonzoo Try with this tool, with this you can change inform url inn batch, work with EAP Gateways and Switch.

https://www.tp-link.com/en/support/download/eap245/#Omada_Discovery_Utility

Remember to login witch device id not controller username,

@shberge 

Tried with the latest discovery tools, but no way to receive the inform to the new controller, "Adopting Time Out" is only the message back from the device. This is a case issue if indeed your offsite controller change his Wan IP. Then apparently the only way to re-adopt the devices is to use the reset button procedure on site :-( I'm waiting from long time to have a possibility to add an URL and not IP into the OPTION138 dhcp server router. or give a dedicated OPTION to use URL inform into Router SDN settings.

@Fae can you advise what's the procedure in case of offsite controller lost/change IP ?

@Pascal 

You can use url in discovery tool. and you have to open TCP 29814 if you use Omada SDN 5.0.30 to adopt to a remote controller.

but url in option 138 have ben nice and easy.