Information:
gtkmail is a fully MIME-compliant e-mail client for X-11. It uses the Gtk-- widget set and supports standard UNIX mbox-style mailbox files, so it can co-exist with other mail clients like PINE.
It also has complete MIME support, POP3 and IMAP4 mail fetching, base64 and quoted printable decoding, and
regular expression-based mail filtering.