Must is an interesting word. I'm pretty sure I didn't use it. Not have I used authorized, mandatory, recommend. I don't have my controller in front of me, but I have UAV toolbox that I use. I also use x-plore file explorer. I also used the document editor to peak at the data stored on the ST-16. I have installed other apps such as datapilot, pix4d, precisionhawk to see what info if any I could gather from these apps and the data they collected. I also fly a DJI and it's nice to have one device to store and access your data. I never said you should be snapchatting while flying, just how to place an app on the accessible Androids desktop within the controller. Maybe some can discover some useful information to be shared.