Every telephone system will eventually start to show its age. The old system may no longer be able to fulfil requirements such as connecting branch locations and home offices to the system, migrating to promising VoIP technology, or adding additional extensions. When acquiring a new telephone system, a seamless and costeffective migration to future-proof technology is desirable. Usability and presence management, which provides real-time information on the availability of co-workers, are key considerations here. The new communication system needs to be able to seamlessly integrate into the company’s communication environment.