@jillian @jple and other ISRG staff working on the ACMEv1 deprecation: I have to say that this has all been handled really effectively by Let's Encrypt, including the long lead time, the notification e-mails, and the incremental brownout strategy. The volume of questions so far is minimal!
As @griffin and others have pointed out, it may be that there will be some kind of spike in questions in September as the last certificates on v1-client-only systems expire without renewal—but I suspect even that will mostly be spread out randomly over the next three months. (The first such certificates have already begun to expire yesterday and today, and others will continue expiring until September, by which time all of them will be expired.)
So while there are probably some users running into this problem, you've given people a lot of information and a lot of opportunities to find out about it. It doesn't look like there is a crisis, and it doesn't look like there will be a crisis.
Also @petercooperjr and @griffin, and really the whole forum community, have put out helpful information about upgrade options for specific clients, both just now and in many individual forum thread answers over the past year. If people come to the forum and search for information about their ACMEv1 upgrade situations, they're very likely to find a great answer here already.
