Version 4.8 was originally intended as a kind of "Version 5 dressed as version 4" release of Mercury. It has several significant new features that were originally flagged as V5 features, but because they are all quite fundamental, in the end I decided that it was fairer to release them in a way that would allow current v4.x licensees to gain access to them without requiring a new license. Over the course of its development, though, v4.8 has ended up taking on the feature list of a major release in its own right.
- OpenSSL All Mercury modules that support secure connections using SSL/TLS now use the industry-standard OpenSSL libraries to do so. Using OpenSSL means greater interoperability with other sites, and allows the use of fully-signed certificates - indeed, Mercury even provides an easy, step-by-step generation process to create the CSR requests needed to purchase or acquire such certificates from online Certification Authorities.
- TCP/IP overhaul The Mercury TCP/IP code, which is the core code that interacts with the Internet, has been totally overhauled. The main benefit of this comes with improved reliability and maintainability, which will make it easier to update the program in future - but you may also notice Mercury handling connections rather faster than in previous versions as well.
- Completely rewritten help system Back in the days of Vista, Microsoft ceased supporting the ageing but functional WinHelp system, but failed to replace it with anything satisfactory (HTMLHelp, in particular, could not be used if the help file was installed on a shared volume, as Mercury frequently is). I finally completed my own help system in time to use it to host a completely reworked Mercury help file for this release. The new help system is up-to-date, consistently formatted, and much more usefully presented than the old version; it will also run properly no matter where Mercury is installed, or on what version of Windows it is running. The new system has a comprehensive table of contents and index, with free-text searching planned for future releases.
- SSL support in MercuryE The MercuryE SMTP client now has comprehensive support for SSL connections in outgoing mail, and has an Access Control List that allows you to fine-tune connections and SSL usage for specific servers and domains.
- Direct-connect SSL support in MercuryS and MercuryP The MercuryS SMTP server and MercuryP POP3 server now support direct-connect SSL, even though direct-connect SSL is formally deprecated by the Internet Standards Body. With the proliferation of low-quality cellphone mail clients, though, supporting direct-connect SSL has become unavoidable. Direct-connect SSL is turned off by default in both modules, but can be enabled in the 'SSL' settings page for each.
- Mercury IMAP search rewritten The part of the Mercury IMAP server that implements searching has been completely rewritten: it should now handle any valid IMAP search expression (the old version had trouble with some operations) and should do it noticeably faster than the old version did.
- Mercury IMAP fixes and improvements The MercuryI IMAP server has had numerous fixes and improvements made. Thunderbird users in particular should now find it works much better for them.
- DMARC support for mailing lists DMARC is a convention used by a number of large sites, including Yahoo, which limits the hosts that can send mail for e-mail addresses in their domains. This plays merry hell with mailing lists, without providing any very good way of mitigating the problems. Mercury v4.8 does the best it can it encounters DMARC-restricted addresses in mailing lists, but our advice to you is the same as that of many other makers of mailing list management software - for the best experience using a mailing list, tell your subscribers to subscribe using an address that is NOT affected by DMARC.
- Many, many bug fixes Behind the scenes there have been dozens of corrections made. While many of these were exotic and seldom-encountered, the overall effect is to improve the reliability and robustness of the program considerably.
As well as these features, Mercury now includes a commandline utility called HS.EXE which can be used to locate messages matching almost any header-based criteria very quickly and efficiently in directories containing large numbers of mail messages, such as spam repositories.