`mailer_command` was removed, and a new setting `send_mail` was added.
Its possible values are a string, consisting of a shell command to
execute, or settings to configure an smtp server connection. The
configuration I used for testing this is:
[composing]
send_mail = { hostname = "smtp.mail.tld", port = 587, auth = { type = "auto", username = "yoshi", password = { type = "command_eval", value = "gpg2 --no-tty -q -d ~/.passwords/msmtp/yoshi.gpg" } }, security = { type = "STARTTLS" } }
For local smtp server:
[composing]
send_mail = { hostname = "localhost", port = 25, auth = { type = "none" }, security = { type = "none" } }