MailerQ 5.15.3

We have released a new minor version of MailerQ. This update focuses on improved reliability, better message parsing, and several important fixes. Please check the release notes for more details.

Improvements to reliability and message handling

This release includes a fix for a rare race condition that could cause MailerQ to hang during shutdown under heavy load. Additionally, when a message from a temporary queue cannot be instantiated, MailerQ now logs the complete message JSON, making operational troubleshooting significantly easier.

The DNS subsystem has also been updated to DNS-CPP 1.4.0, improving performance by allowing DNS contexts to share sockets more efficiently.

Improvements to MIME and DSN processing

We’ve resolved multiple edge-case issues in MIME header handling and message decoding logic, ensuring more stable processing of a wider variety of message formats. An off-by-one bug in Xtext decoding has been fixed as well.

A major set of fixes improves the handling of delivery status notifications (DSNs) received from several MTAs, including Web.de, GMX, Exim, Qmail, MS Exchange, and T-Online. These fixes address incorrect handling of non–null-terminated data, resulting in more reliable extraction of original messages and more accurate DSN parsing.

Bug fixes

A number of low-level parsing issues have been addressed to prevent exceptions, crashes, or malformed data when processing unusual or incorrectly formatted messages. MIME parsing is now more robust in edge cases, reducing the likelihood of operational errors.