As the Teradici CTO, let me add a little color to this discussion. When support for Network Appliances (e.g. Cisco, F5,...) was added to the protocol (back in View 5.x), this created a new authentication scheme to allow these devices to be an authorized-man-in-the-middle. We did not have the ability to support both the old and the new authentication scheme in the Tera1 devices so they stayed on the "old scheme". Starting with Horizon 6, VMware is only certifying clients that use the new authentication scheme and have not indicated that they will add any new capabilities nor provide support for clients that use the old scheme (which includes older software clients, too).
Because of the large install base of older clients, I do not expect that they will disable the old authentication mode. Since they are not doing any new feature development in that mode, they are also unlikely to break compatibility. However, fixing any issues that might arise for "old mode" clients is not committed by either Teradici or VMware. which is why we have made this End-of-Life announcement.
Tera1s have been on the market for 8 years and we stopped selling new chips to our partners 3 years ago. You will notice in the KB that we are providing "technical guidance" until December 2016 which will give everyone at least 5 years of guidance even if you were one of the last customers to buy a Tera1. Even as CTO, I have several Tera1 devices in my various offices (in fact I am using one right now). I am running pre-released code that is even beyond Horizon 6.1.1. I fully expect that they will continue to work well beyond December 2016. However, if you need new Horizon features or the new capabilities in Tera2 devices, then you will need to upgrade. If you need a guarantee that your Tera1 devices will continue to work on future Horizon releases, then you should also upgrade. Or, you can just keep using them until a Horizon release comes out that breaks compatibility with the old authentication mode - if and when that occurs.
We just want to be clear about the facts so you can make an informed decision.
Randy Groves - Teradici CTO