Most updates are not new features. They close holes that attackers already know about — which is why postponing them repeatedly is the risk, not the update itself.
The drawing that proves the sentence above. It is the same card that is in the book.
Think of it as
a service for the car you drive every day.
For example
A message keeps asking to update and you keep saying later. The update is mostly locks being changed — and you keep saying later.
This is one card out of 275.
The hundred words you meet most are free — the whole set, animated, in one file that works with no internet.
Volume 1 has all 275 in fifteen chapters, with Staying Safe the largest chapter on purpose.