In the "Device Editor" category, you will find two new settings in the "Options" dialog (menu command "Tools > Options"):
Checkbox Create cross references for IEC addresses (clean necessary) If this checkbox is active, unused I/Os (I/Os which are not mapped) will be found via Find/Replace and the cross reference list.
Checkbox Use classic communication page As of PLC Designer V3.9, a different communication page can be used. Advantages of the new communication page:
IP address of controller can be saved in the project.
Addresses of preferred controllers can be managed and easily selected from the drop-down menu.