Zend Server allows you to install, and consume, PHP libraries used for running applications in your production environment. Since they no longer need to include libraries, application packages can now be much lighter. These libraries can be anything from a family of files or functions, to fully structured feature-rich frameworks.
If you have applications using different versions of the same library - no problem. Zend Server enables you to install parallel versions of the same library, thus giving you full usage flexibility.
Libraries can also be redeployed and removed if necessary. Zend Server will automatically check for available updates for the deployed libraries, but you can also manually check for updates.
By default, Zend Server includes the following installed libraries: Zend Framework 1, Zend Framework 2, ZendServerSDK, Symfony
The installation of additional libraries is done using the Zend Server Deployment mechanism, and necessitates an application package file (.zpk).