The Bat! has been regarded as an alternative email client for advanced email users. It is often praised for its focus on security, as well as user interface customization and filtering capabilities.
1.0 Beta, the first public version, was released in March 1997. It supported folders, filtering, viewing HTML email without the need to have Internet Explorer installed, and international character sets. It also had a special feature named Mail Ticker.
1.00 Build 1310, the first stable version, came to public in March 1998.
1.32 introduced a proprietary layout engine on 27 April 2000. Versions up to 1.31 had used the THtmlViewer engine by David Baldwin.
Version 4.0 (February 2008) has Address History option, Favorite Folders sets and URL manager for HTML images retrieval. The Bat!'s text editor supports Unicode, internal image viewer supports rotate, advanced resize and zoom algorithms and full screen mode.
Version 4.1 (December 2008) adds HTML templates, support for SOCKS proxy, and a new mail database format that allows for an unlimited volume of mail.
Version 4.2 (June 2009) adds postponed sending.
Version 5.0 (April 2011) improves support for IMAP protocol, hints, folder information html templates, image downloader, odd/even row contrast.
Version 5.1 (April 2012) adds Inbox Analyzer, image download manager, message tags, hints, external HTML viewing module and Multi-SMTP option.
The client's name was included as a preset for forging the X-Mailer software user agent identification header in a popular mass-mailing tool. SpamAssassin rules now include detection for such forged headers.
^Glitman, Russell (17 February 2004). "The Bat! 2.0". PC Mag: pp. 68. Retrieved 14 June 2012.
^Randall, Neil (November 2005). PC Magazine Windows XP Solutions (2 ed.). Wiley. p. 163. ISBN0471747521. "along with its templates and forms, and its highly sophisticated filtering and sorting systems, this feature demonstrates its ties to the business community. But it's also of considerable use on non-business PCs, particularly if you grow tired of Outlook (or don't want to buy Outlook."