Used GNUMail.app for Mac?
Developer’s Description
Version 1.1.0 has the following supported features: Multiple POP3 (with APOP support) accounts with local cache support (for leaving messages on server); Multiple delivery agents (SMTP or local mailer); Mail spool file support for receiving; Good IMAP support with local caching; Full RFC822 and RFC2822 support; Read, compose, bounce, reply and forward mails; Mailbox management (create, delete, locking and transfer messages) using the Berkeley mbox format; Personal preferences management; MIME support (decode and encode); A full MIME types manager; Quoted Printable and BASE64 support; Address Book with groups support; Find Panel with regular expressions support; Automatic or manual fetching of your mails (user's choice); Powerful filters that support regular expressions; GPG (PGP) support through a bundle; Messages threading.
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