XiVO.solutions refers to the open-source, IP-based telephone and communication system called XiVO, developed by Avencall (now part of Volaris Group). It is a comprehensive solution for businesses that includes PBX, voicemail, and call center features, built on the Asterisk platform and distributed under the GPLv3 and LGPLv3 licenses. The system is known for its scalability, web-based administration interface, and features like a provisioning server and CTI integration.