Ok, maybe I misunderstood the purpose of this function. I wanted to use it to check if the timestamp is active or inactive and I tried to get it by using (org-at-timestamp-p 'inactive) while pointing at the timestamp. But actually when I call it on any timestamp like [2020-09-04 Fri], <2020-09-04 Fri> I always get nil. So either it's a bug, or I miss something.

Thanks,

Adam