This post is contributed by Catherine Moxey, IBM Senior Technical Staff Member - CICS Performance and Optimization
CICS application multi-versioning is a capability introduced in CICS TS V5.2 as part of cloud enablement for CICS. CICS Cloud support allows your CICS environment to deliver the benefits of cloud computing, built on the solid foundation that CICS provides.
CICS Cloud allows you to define a set of CICS regions as a CICS platform, to define the disparate resources that make up an application as a first-class entity, a CICS application, and to deploy that CICS application onto the platform in a controlled and repeatable way. In addition, CICS threshold policies allow you to control the use of critical resources within an application or platform.
Application multi-versioning is an exciting extension to the initial Cloud support, which allows you to run more than one version of the same application within the same region (or all of the regions in a region type within a CICS platform). You can be running version 1.0.0 of an application, realize it has a bug, fix the problem and deploy the fixed version of the application as version 1.0.1, and then by making that version available, immediately and without loss of service allow users to start getting the fixed version. Or, you could make an enhancement, and introduce version 1.1.0 of the application in such a way that a subset of early access users initially try the enhanced version, while everyone else continues to use version 1.0.1.
If you want to know more about this, take a look at the IBM Redbooks publication on Cloud Enabling IBM CICS.