If this is too speculative and/or disruptive for this list these days,
please ignore it with my apologies, but...
I came across JMAP (jmap.io) this weekend, and have been looking at it in
my spare time. It looks like it intends to solve most of the problems that
I personally had with mixing mh-style and mobile-app email usage, and might
even be a (speculation warning) useful bridge to the future for nmh. I
certainly remember a time when skipping over IMAP would have seemed crazy,
but the people on emacs-devel are currently wrestling with the implications
of at least Google and MS both moving towards shutting down pure IMAP
access (somewhat stalled by current conditions, but clearly stated intent).
If anyone here had a considered opinion, I'd like to hear it.
Thanks,
~Chad