Thanks, unomia. The Codex must be out of date.
You can also access the same Announcements subscription via the download page https://www.ads-software.com/list/
However, I was already subscribed to this, and don’t seem to have been sent anything about “WordPress 4.7.5 Security and Maintenance Release” which appeared on the blog yesterday.
A simple mailing list for security releases would be very helpful in keeping WordPress secure for those who don’t log in to a dashboard daily, or stay a minor version number behind. It would benefit system administrators, site builders and owners. An archive to show previous announcements would also help.
A rather desperate solution is to add text alerts alerts at https://profiles.www.ads-software.com/%5Busername%5D/profile/notification