The two versions can run in parallel so you will never be in a situation where the sysadmin is forced to take down the v1 server to set up a v2 server. It's the

The two versions can run in parallel so you will never be in a situation where the sysadmin is forced to take down the v1 server to set up a v2 server. It's the sysadmins responsibility not to put users in that situation. Users might try to use the wrong version at first, but there's no reason for an admin to break the working VPN before the transition is complete.