Best answer: No. While Google adjusted the Chromecast lineup in 2019 by discontinuing the Chromecast Audio, both the 3rd Generation Chromecast and 4K-ready Chromecast Ultra are still widely available and supported.
- The future-proof 4K dongle: Google Chromecast Ultra ($69 at Amazon)
- Best value for non-4K TVs: Google Chromecast (3rd Gen) ($35 at Amazon)
There are two Chromecasts available (but there's only one you should buy)
Google has released three versions of the standard Chromecast, starting with the original Chromecast streaming stick that was released back in 2013. Google would refresh the Chromecast lineup in 2015, which is when they revealed the disc-dongle design that it has defined Google's streaming devices ever since.
The 3rd Generation Chromecast still works great, but if interested in buying a new Chromecast in 2020, you should really only consider getting the Chromecast Ultra. The Ultra is the crown jewel in the Chromecast lineup, offering support for 4K and HDR and an ethernet port for a hardwired internet connection.
It's also the dongle Google includes with the Stadia Premiere Edition, so that's the bundle to get if you're interested in Google's game streaming service. At the very least, you get a well-designed controller and get to experience everything that the Chromecast Ultra can do. However, they are discontinuing the Chromecast Audio; so if you have one of those, it's time to upgrade.
Get the Chromecast Ultra even if you don't already own a 4K TV
The Chromecast Ultra is Google's dongle of choice as it goes forward with Stadia. Still, there's been no indication that the standard Chromecast is going to be discontinued anytime soon. There's even a curious line in the Stadia FAQ regarding older Chromecast models that says to "stay tuned for future announcements regarding additional device compatibility.
Reading between the lines, that would appear to suggest that at some point, the Stadia will be compatible with standard Chromecast dongles and other Android TV boxes and smart TVs with Google Cast functionality, albeit not in 4K resolution. Even still, you're better off getting a Chromecast Ultra now rather than waiting for Google to add a new feature to older products.
The best Chromecast you can get
It's double the price of the standard Chromecast, but you can stream in 4K HDR and get an ethernet adapter in the box. At this price, your options for 4K HDR streaming are limited, so the Chromecast Ultra is a great choice.
Chromecast (3rd gen)
The cheapest way to get into Chromecast
If you're looking for the cheapest possible way to start streaming to your TV, the 3rd-gen Chromecast fits the bill. It's half the price of the Ultra, making it appealing for anyone who doesn't stream 4K or wants to connect a secondary TV.