Firmware Over the Air updates using Pelion and mbed OS

Hello, I have found a paper on how the FOTA updates are taking place using LoRa and mbed OS however I would like some information on what is running on the GW? As I can understand I have to add my GW and my end devices to pelion portal. Am I correct? Also, for other protocols (like 802.15.4) how the FOTA is taking place? Is the code open?