Check if they need update (October surely, December depending on how old was the stock). When you run the LoraSandAndReceive example, you will see the firmware version (Your module version is: ARD-078 1.1X); current one is 1.1.9.
If you are using the Arduino IDE, you can then update the library as any other (Manage libraries, choose "updatable"; last of MKRWAN is 1.0.9).