"Subscribing" to forum topics and other website postings

There used to be a feature on the website whereby one could "subscribe" to website forums and other postings, with the result that one received an e-mail whenever a new topic was started or comment added.  This feature seems to have disappeared since the website was updated recently, and I am no longer receiving the e-mails - the only way of discovering what new postings there are now seems to be to log in to the website and have a look.

The help/posting-to-forums page has a note (at the bottom) that "The 'Forum Tools' dropdown allows you to perform useful admin functions" but if that feature is still available, I can no longer find it.

Is this feature still there, and if so how do I set it to work again?

Yes, I think "mark all posts as read"  has also disappeared.  The "Forum Tools" were possibly only used by regular Forum geeks like John and myself but they were very useful!

I asked people in the know. The reply “It's not available yet in Drupal 9, but Stuart is looking at options.”