Hi @John-And-Lani0
You can still click a specific booking and make the note on the booking itself, or you can use the multi-calendar (if you're using professional hosting tools), to make the note. The multi-calendar has not changed at all with the update, as far as I can tell.
However, many hosts want to make a note on a blocked date (to state the reason why they're blocking it). As there's no reservation to click, this is now not possible on the regular calendar.
I'm in an ongoing support query with the technical team where they're looking into these issues, but it's taking some time. As @Joelle43 says, if many hosts report it, it may help a great deal. Be sure to make it very clear that you're talking about the regular listing calendar, not the multi-calendar, and that you're aware of the option to make a note on the reservation. The issue is that the present regular calendar has no notes function for blocked dates.