Coexistence, compatibility, and interoperability

Coexistence is being able to install and run two or more versions of the same program on the same server. For WebSphere® MQ, it normally means installing and running multiple versions of WebSphere MQ on a server. Compatibility is the ability to run applications from one level of queue manager with an earlier or previous level of the queue manager. It is also the ability to run client applications with different versions of the WebSphere MQ MQI client, and different levels of the queue manager. Interoperability is mainly the ability to exchange messages between different versions of WebSphere MQ. It can also mean the interoperability between others things, such as publish/subscribe brokers, or between components such as the WebSphere MQ classes for JMS and WebSphere Application Server.

Maintaining the compatibility, coexistence, and interoperability of WebSphere MQ is important in order to preserve the investment you make in applications and administrative procedures. Three areas to which this objective does not apply to as rigidly, are GUI interfaces, such as WebSphere MQ Explorer, information for service, such as FFST files and traces, and error messages. The text in an error message might change, to make the wording clearer or more accurate.