The person replying to your question seems to be googling the exact answers. Anyone can google or search on this site. They are also using terms that make NO sense.

What did you learn? 

I think the person was saying app but they meant to say upgrade your account, which would be stupid but I think that is QB's way of controlling users. I don't see how that controls users if I have many email addresses and if I can only log in with one but send receipts from my personal and business, it won't affect anything.