RN2xx3 LoRa® module - PCB Design Recommendations
Additional recommendations about the test points on the bottom side of the module:
We recommend avoiding the use of the area below the module. However, if you really need to layout traces on that area, these traces will be painted (solder masked) and the risk of having a conductive contact with our testing points is minimal. However, there is a chance of bringing a noisy trace close to a sensitive clock trace.
Our suggestion is to stay away from that yellow perimeter in case you cannot keep the bottom of this module empty. For soldering reflow recommendation on the RN2483 and RN2903 module, please see the application note AN233.