We issue updates to Firefox when there are serious issues that need to be corrected, or when there are new features that are ready. Keeping your browser up to date is very important to keep yourself safe on the internet.

Do you mean this, a "door hanger" from the menu button:

I think there's a timer so you should only see it every 12 hours. If you open and close Firefox frequently instead of leaving it open continuously, you might see it more often.

If you are getting something else, what does it look like?