The /unlock command should unlatch if your door fitting is configured to use a knob. If it is configured as handle, it will only unlock.
To send the unlatch command even if the door is configured as handle, you need to use the /lockAction endpoint instead and send action 3.
So to follow your example: http://192.168.1.126:8080/lockAction?nukiId=1234567&action=3&token=xxxxxx