The latest version of VTS is available for download on the VTS Versions page. It is always best from a quality and security standpoint to operate with the latest version, though recent older versions may continue to be supported for a while. Eventually, old versions will become unsupported, at which time users must update.
To confirm which version you are running, launch VTS (you do NOT need to log in) and look for the version number in the lower right corner of the screen.