Getting alerts that someone is in my account

[Zzz12345]

One popped up the other day saying it was from Safari on MacOS 10.9. I may have used this OS in the past, but not now. I always wipe my computers so I am curious what happened. I don't see anything like that showing up on my device list, I wonder if it is no longer supported that they can still see my files?

I have changed my password, removed other older devices, enabled TFA.

Any idea what else I can do?

[Walter]

Hi there @Zzz12345, sorry to hear about this.

I assume you've already checked your account's security page for any unknown devices and web sessions, right?

Did you get this notification as a pop-up from the app or a notification on the website? Since you changed  your password, did you receive the notification again?

Any additional information is more than welcome!