This is Claws Mail, a GTK+ based fast email and news client, and whose objectives are having quick response, advanced, easy configuration, and multiple features.
- POP3 and IMAP4rev1 support.
- NetNews client integrated.
- Multiple account configuration and handling.
- Multiple folders support.
- Import / export mailboxes.
- Include integrations with external editors.
- Include message queueing.
- Provide integration with Address Book using XML or LDAP.
- Contact management and vCard support.
- Support APOP authentication.
- Support SMTP AUTH.
- GnuPG support.
Claws Mail is GPL. Further intructions can be found at https://www.claws-mail.org/.