Exim 4.99 Release Candidate 4 released
A new release candidate for Exim 4.99 has been made available. This message transfer agent (MTA) is designed to run on Unix systems connected to the Internet and is distributed under the terms of the GNU General Public License.
Similar in style to Smail 3, but with more general facilities, Exim offers a great deal of flexibility when it comes to routing mail, as well as extensive capabilities for checking incoming messages. One of the key differences between Exim and other MTAs like Sendmail is its configuration process, which is quite distinct.
The fourth release candidate of Exim 4.99 can be obtained in two ways: either by downloading a tarball from the official FTP site or directly from the Git repository using the tag exim-4.99-RC4. The signatures on these release candidate tarballs should match those generated with key ID 0xBCE58C8CE41F32DF and can be verified via email.
As this version is a release candidate, it's crucial for users to test the software thoroughly and provide any necessary feedback so that potential issues can be resolved before Exim 4.99 becomes officially available.
Notably, the source base has been closed for feature additions at this point in the release process, signifying that all changes are now focused on bug fixes and finalizing the product.
The latest version includes several key updates since the previous release candidate (v4.99-RC3). Some of these include:
- Fixes to prevent transport crashes after failed delivery in retry handling and resolve an issue with Exim crashing on local SMTP if the message_id_header_domain contains a hyphen.
- New features such as the sieve_inbox option for redirect routers, the "connection_id" variable, the smtp:fail:protocol and smtp:fail:syntax events, support for omitting Exim and Sieve filters at build time, JSON and LDAP lookup support, PAM, RADIUS, perl, SPF, DKIM, DMARC, and ARC support, as well as the ability to expand transport "socks_proxy" to an empty string.
- Various security enhancements, including the inclusion of fixes for CVE-2025-26794 and CVE-2025-30232.
In addition, several new features have been added since Exim 4.98, such as:
- Support for ATRN (both provider and customer)
- IPv6 address support for mysql and pgsql lookups
- Cut-through deliveries and recipient verification can use an envelope-from a specified transport.
- The options hosts_randomize in manualroute router and smtp transport are now expanded
- Options fallback_hosts in smtp transport and in all routers are now expanded
- Support for SRV records specifying TLS availability.
- Main-section option "log_ports" to filter logged port numbers
- Additional delivery log line element, under the "protocol detail" control, giving the smtp protocol startup sequence
- Log selector "tls_on_connect" to give distinguishable protocol labels for that case in received log lines
- Command-line option for pre-config debug
The tarball can be downloaded from this location or directly from Git.
