On Mon, Feb 08 2016, David Edmondson wrote: > On Fri, Jan 15 2016, Daniel Kahn Gillmor wrote: >> So where is the case-insensitive lookup happening? Is this a bug in >> mml-mode, or in notmuch-emacs? > > It's caused by behaviour in mml2015.el (hence upstream). > > `mml2015-epg-check-user-id' uses `equal' to compare the recipient from > the composition buffer with the addresses from the matching key. > > The simplest way to get the desired behaviour would be to `downcase' > both strings before comparing. Reported as bug#22603 in emacs.