A quick preview of what will be documented in a future Firmware release:
AT+WDM=0
Resets the development mode persistence (the persisted port will return to production mode after a target reset)
AT+WDM=1
Asks for development mode to be persisted on the current port (the current port will stay in development mode even after a target reset)
AT+WDM=2
Just a query command to retrieve the current port ID
AT+WDM?
A query command to retrieve the development mode persistence state (0/1), and the port ID on which the persistence has been configured.