I googled "JAMF Yosemite" and got a link to Make the transition to OS X Yosemite gracefully. Clicking that I got the following error:
So is there no graceful transition? It seems when users upgrade, the local accounts get locked out and the only workaround is to rebuild the device.
The cached version isn't very helpful either. All it says is that the Casper suite will help in the transition.