What's changed in IBM MQ 9.4.0 Long Term Support

The Long Term Support (LTS) release is a recommended product level for which support, including defect and security updates, is provided over a specified period of time.

LTS releases do not deliver new functional enhancements. They contain only defect fixes and security updates, and are made available at regular intervals. They are intended for systems that demand maximum stability over a long term deployment period.

For more information see IBM® MQ release types and versioning and IBM MQ FAQ for Long Term Support and Continuous Delivery releases.

For Long Term Support, maintenance updates for IBM MQ 9.4.0 for Multiplatforms and IBM MQ Appliance are provided as fix packs or cumulative security updates (CSUs).

Note: From 1Q 2023, for Multiplatforms, there are two types of maintenance:

Fix packs, which contain roll-ups of all defects fixed since the previous fix pack delivery (or GA). Fix packs are produced exclusively for Long Term Support (LTS) releases during their normal support lifecycle.
Cumulative security updates (CSUs), which are smaller updates and contain security patches released since the previous maintenance (GA). CSUs are produced for LTS releases (including releases in extended support), and also for the latest IBM MQ Continuous Delivery (CD) release, as required to deliver relevant security patches.

For maintenance releases in or after 1Q 2023, the fourth digit in the VRMF represents either a fix pack number or a CSU number. Both types of maintenance are mutually cumulative (that is, they contain everything included in older CSUs and fix packs), and both are installed using the same mechanisms for applying maintenance. Both types of maintenance update the F-digit of the VRMF to a higher number than any previous maintenance: fix packs use "F" values divisible by 5, CSUs use "F" values not divisible by 5.

For maintenance releases before 1Q 2023, the fourth digit in the VRMF always represents the fix pack level. For example, the first fix pack of the IBM MQ 9.3.0 LTS release is numbered 9.3.0.1.

For more information, see Changes to IBM MQ's maintenance delivery model.

[z/OS] For z/OS®, maintenance updates are provided as Program Temporary Fixes (PTFs) or cumulative security updates (CSUs). For z/OS UNIX System Services features (that is, JMS, REST API and IBM MQ Console, and Managed File Transfer) the z/OS PTFs are aligned directly with the Multiplatforms fix packs. Other PTFs are made available as and when they are produced.

IBM MQ 9.4.0 Fix Pack 5

New return code 2491: IBM MQ 9.4.0 Fix Pack 5 adds a new return code (2491) that can appear in messages that are moved to the dead letter queue. For more information, see 2491 0x000009bb MQRC_MSG_LENGTH_ERROR.