I switched my default mail provider to iCloud, instead of this domain name. Back in time, I guess. This way I can manage my emails using Neomutt or Apple Mail (via IMAP), depending on my mood, and everything keeps sync’ed. I needed to convert my archives folder from Maildir to Mbox but Neomutt failed me when I used the following command:
neomutt -f ~/.mail/archives -e 'set mbox_type=mbox; set confirmcreate=no; set delete=no; push "T.*<enter>;s/Users/chl/tmp/archives.mbox<enter><quit>"'
I believe this doesn’t handle multiple aliases for sender correctly. However, this Python module worked like a charm and I was able to get 10k messages with correct threading in no time at all.