In versions of Iguana prior to version 4.0, the source and destination components of a channel were tightly coupled. When the channel's source component received a message, it passed the message to the destination component that it was coupled with. The destination component would then attempt to process the message. The result of the attempt to process the message would be transmitted to the source component.

In version 4.0 of Iguana, the source and destination components are decoupled. Each source component of a channel receives messages and passes them to a message queue. Each destination component of a channel receives its messages from this message queue and processes them as needed. This decoupling of source and destination components enables Iguana 4.0 to be much faster than previous versions.

However, because the source and destination components are now decoupled, channels interact with messages and applications in slightly different ways than they did in versions of Iguana prior to version 4.0.

The following sections describe two examples of ways in which the behavior of channels in Iguana 4.0 is slightly different from the behavior of channels in older versions of Iguana.