Enforce the minimum client version

The administrator sets the minimum client version (see Requiring minimum client version in Helix Core Server Administrator Guide).
A user who has a version of P4V that is older than the minimum client version attempts to start P4V and connect to the Helix Server.
The user is not allowed to connect and is displayed a dialog to upgrade to the newest P4V version.
As soon as the upgrade is installed, the end-user can start P4V and connect to the Helix Server.