Viscosity software (version 1.4.9) is a VPN client for Mac and Windows operating systems. It offers advanced features such as DNS leak protection, IPv6 leak protection, and kill switch to ensure secure and private internet connections. The software also supports OpenVPN, L2TP, and PPTP protocols and provides detailed connection statistics and logs for troubleshooting. Additionally, it allows users to import and export VPN profiles for easy sharing and configuration.