I work with many customers in the course of my job on Citrix upgrade projects. Common scenario, Presentation Server 4.5 to XenApp 6.5 upgrade. One thing I see often overlooked by the customer in their planning (beside app compatibility with Windows 2008 R2) is the clients that are connecting to this infrastructure. In typical server administrator fashion we focus on the datacenter and the backend infrastructure, you know, the cool shit (insert manly growl).
Well, that fancy upgrade isn’t going to be noticed by your users, except that they website probably looks different and Windows start button is gone, if you don’t take into account an upgrade plan for the client software on the endpoints. The Windows and Mac machines can be tricky, and functionality that used to exist like launching apps from the system tray might be gone, but these are all things that can be overcome with time and training.
The hard ones I’ve found are projects that didn’t take into account that the thin clients connecting to the environment might not support that latest version of Citrix Receiver, even worse they might not support a version of Citrix Online Plug-in that is tested or supported against XenApp 6.5. Now we’re going to have a tough conversation, because it’s no longer something we can overcome with training, email blasts, and time…you’re going to have to spend money.
The Citrix stance on support for client software is non-existent from what I can find, but I remember something about supporting the current version and 1 major version back. In the system requirements for Citrix XenApp 6.5 they mention they tested with Online Plug-in 12.1 but some features are not available. My general suggestion is you need to be thinking about how to get to version 12.x…if you can’t get there you need to think about buying new thin clients, changing your client strategy, or accepting the risk. I’ve seen ICA v7.x clients connect to a XenApp 6.5 farm :)
If you’re using thin clients, they don’t last forever, in fact their useful lifetime is probably not defined by the hardware but rather the software they support (see post on BrianMadden.com). Thin clients add complexity, it’s a world of choices and there is no perfect solution, just don’t forget them in your upgrade budgeting and planning.