The tendency is to think of routers like an appliance, but believe it or not they have firmware (that is somewhere between hardware and software) that controls their operation and that needs to be updated occasionally, for a couple of reasons:
- SECURITY: In the past year a vulnerability in network protocols was discovered and patches/updates were released to many routers to remove that vulnerability.
- Bugs: Developers make mistakes and bugs do creep in
- Speed: Wifi protocols are evolving. In roughly the last ten years WiFi standards have evolved from 802.11b through 802.11g and 802.11n to 802.11ac and there is talk of 802.11x. Each change has improved WiFi speeds added additional frequency bands, channels, improved channel spacing, etc. all while maintaining backward compatibility to older standards which is a neat trick.
The first two items can be fixed in a firmware update the third can sometimes be a firmware change depending on design and implementation but is more likely to require new hardware. If your MacBook was built in 2014 or later it is capable of 802.11ac and you might enjoy a noticeable bump in internet performance if your router were also capable of 802.11ac and you are connected using a channel in the 5GHz band.
The point is: Routers do need to be updated but the mechanism for updating routers varies from manufacturer to manufacturer and possibly even from model to model and is known to very few users. If, and that is a very big if, you have registered with the router manufacturer they will generally notify you of updates and instructions on how to install them when they occur. If you did not register you are on your own. My mesh router for several reasons keeps in contact with the manufacturer and downloads and installs updates late at night when there is little or no network traffic and I only way I ever know about it is if I happen to be up and notice the tiny light on one of the pucks slowly blinking off and on.
You mentioned antenna on the newer routers, those are intended to help shape the WiFi radiation pattern and thereby extend the signal further in a desired direction. My mesh router on the other hand extends its signal via multiple small low powered antenna-less pucks scattered through the house talking among themselves on one band and generating their own signal on both 2.4 and 5 GHz bands for the various devices to connect to.
