I apologize for my bad english beforehand, it is not my native language. I was going to buy this router:

TP-LINK Archer MR600 -4G+ LTE

I was looking at how to start the device but then I read from tp-link website that 

"Note: Low version of your web browser may cause compatibility problems with the web-based interface (management page) of your device, such as unable to log into the interface, display incomplete features, etc. It is strongly recommended to use a wired connection if you are going to change the router’s wireless settings or upgrade the firmware version of the router.." 

https://www.tp-link.com/uk/support/faq/1656/

I do not own a computer, just an old iPhone. I don't think there is a wire that connects iPhone with a router? It also reads elsewhere about some other tp-routers firmware upgrade info that "It is NOT recommended to upgrade the firmware wirelessly." I don't know if all routers, not just tp-link has this risk? I also assume that it updates automatically and doesn't need to update manually..?