Which two prerequisites and considerations must be met prior installing Avaya IX™ Messaging?

[Reference:http://www.esna.com/services/education/IX_Messaging_10_8/TOG/RH5_IXM_TOG/IXM_TOG_System_Requirements/IXM_TOG_System_Requirements.htm, , Before installing Avaya IX™ Messaging, it is essential to ensure that the server has the operating system installed, patched, and completely updated to provide a stable foundation for the application. Additionally, the corporate telephone system and PBX must be installed and functioning properly to ensure seamless integration and communication capabilities with Avaya IX™ Messaging., References: The prerequisites for installation are detailed in the Avaya Messaging Support Learning documents, which outline the necessary steps and considerations to prepare for a successful deployment of Avaya IX™ Messaging., , ]