K-9 Mail for Android

To retrieve mail via IMAP
imap server	`mx.sdf.org`
Security	`SSL/TLS`
Port	`993`
Username	`sdf user name (eg, alan8r)`
Authentication	`Normal password`
Password	password associated with sdf user above

To send mail, set up SMTP with
SMTP server	`mx.sdf.org`
Security	`STARTTLS`
Port	`587`
Username	Your web domain name¹⁾@sdf.org
Authentication	`Encrypted password`
Password	string set via mkvpm set YOUR_PASSWORD_HERE

K-9 Mail for Android - traditional link (using RCS)

¹⁾

If you are a Meta-ARPA member and not a VHOST member, this is whatever web domain you've chosen–frequently username.sdf.org. If you're a VHOST member, it's your VHOST domain–like yahoo.com@sdf.org