I get those emails, too, but no appointments are showing up for me.
When I was trying to book all last week, everything was waitlisted. And, being in Halton, I'm not allowed to use the Ontario booking system, so I had to take what they gave me.
Here's the kicker... we were booked for boosters at our Shoppers on the afternoon of dec 16. We showed up, only to be told we had to wait 2 days, because that was only 166 days from our 2nd shot. That night, it was reported that Ford changed it to 84 days. Of course, by that day, Shoppers were all waitlisted. They refused to rebook me and said the shot that had been allocated for me would go to a waitlisted person, so it wasn't even like it would be an extra in the batch (which is why they couldn't book me in on the Friday). Anyway, I was lucky to get in on Dec 22 on the Halton system, but only because the 18+ people hadn't started booking yet.
Maybe they've opened spots up, now? I hope so.
Also, when is my 17.5 year old going to qualify for a booster?