I'm not sure what is so sneaky, if you are up to date with iOS 14, then the only available update would be 15 right?
The notification would appear if you check manually or automatically download the latest update.
I remember seeing that on a iOS 14 device that the option for 15 was at the bottom....but assumed that iOS 15 would be in the forefront once the device had the latest iOS 14 release.
Before yesterday, users in iOS 14 would continue getting security updates to iOS 14 (latest one being 14.8.1) and would have the option to update to iOS 15 if they wanted. The option to update to iOS 15
was only shown inside the software update section (towards the bottom of the screen). This was an amazing change by Apple because users who did not want to upgrade to the latest and "greatest" would not be constantly harassed to upgrade to the latest version.
Since yesterday, Apple has decided to go back to nagging with badges to the settings app in the home screen (which there is no way of removing/turning off) and showing a banner right above airplane mode (once you enter settings) to advertise iOS15.
I find it sneaky because they lead on as if it was going to be this way going forward. Had they said back in September when they released iOS 15 that they would only give iOS 14 users 2 months of space to upgrade to iOS 15 before beginning their historical harassment tactics, I would be ok with it. But that was not the case.
I'm ok now, I've followed the advice to just remove the settings app from the main screen and hide it elsewhere ?