• In Iguana 4.0, source and destination components are not directly connected to each other. Source components add messages to a message queue, and destination components retrieve their messages from this queue. This means, for example, that an LLP Listener source component is now able to receive and acknowledge messages without having to wait for the destination component to process them.

	Because source and destination components are no longer directly connected to one another, channels in Iguana 4.0 interact with their connecting applications in a slightly different way than channels in Iguana 3.3 did. See Source and Destination Components Are Decoupled In Iguana 4.0 for more information on how source and destination components now relate to one another and to the applications that they connect with.

• In Iguana 4.0, a database is not required unless you are specifying a database as a source or destination component for a channel. See From Database or To Database for information on using a database as a channel component. Because a database is only needed for these specific channel components, Iguana 4.0 requires far less database processing time and data storage space than earlier versions of Iguana.
• In previous versions of Iguana, if a channel was reading from or writing to a database, the server and its other channels could not process any messages or perform any other activities until the read or write task was completed. This could adversely affect system performance. In Iguana 4.0, reading from or writing to a database is performed as a separate task (in a separate thread), which ensures that the Iguana server and any other channels that are defined can continue to function without interruption.
• Iguana 4.0 now connects to databases more efficiently. Database connections only persist for as long as they are needed, which means that Iguana 4.0 requires significantly fewer database connections than were required by earlier versions of Iguana.

For these reasons, using Iguana 4.0 or later will provide significantly better performance if your channels process a significant number of messages.