VyprVPN Desktop is currently compatible with Windows Vista, Windows 7, Windows 8, and Windows 10. It is also compatible with Mac OS X 10.10 Yosemite and greater.
For OS X 10.7 Lion and 10.8 Mountain Lion, you will need to use the last supported version of VyprVPN.
For OS X 10.9 Mavericks, you will need to use the last supported version of VyprVPN.
If you need any further assistance, please contact support.