Version 20 is more than a new version. V20 is the future of 3CX. With V20 we’ve re-architected 3CX from the ground up – ready for current and future market realities. Originally, 3CX was designed for on premise – phone system only – installation, and targeted at SMB/Mid size companies. In a time when hardly anybody used SIP trunks and everybody still had a fax.