Apple

You can sign up for email notifications after creating an account on ipsw.me. Been using this service for many years now, works fine. Emails arrive only minutes after new releases.

I have no idea. I usually just wait until there’s the red circle thing on the settings app lol

I'm in a discord server that pings every time there is a update

Macrumors.com

There is an option for automatic critical updates

Someone on this sub will always post it within the hour normally

Visit the r/apple, r/ios, and r/iPhone subs every day. At least a dozen people per sub will post the second it is released.

I usually check daily around 1pm my time but especially on Tuesdays. But given that my News widgets are for “Apple” and “Technology” and that I follow every Apple product sub for a product I own, I’m usually made away fairly fast