I'm running long-out-of-date versions of Netflix on these just fine:
1. Wii U (2012) whatever came on it.
2. Samsung 3D Blu-Ray Player (2013) pre-loaded version
3. Apple TV 2nd Generation (2010) pre-loaded version
4. RCA Streaming box (2010? found in garbage)
5. Various smart TVs of all vintages (oldest from 2016, an LCD WebOS TV)
6. Galaxy Note 10.1 tablet (2012) side-loaded older version for Android 4.x. Works fine
The UI of the older devices/apps is preferable since there's no auto play crap or weird UI messes, and the 'your list' is easier to locate. I'm convinced that Netflix never gets EOL'd on anything. It's literally the last working app on many outdated smart devices.
I remember not too long ago my LG Smart TV and other smart TVs were supposedly EOL for Hulu because I got emails from Hulu about them, and not sure if those were scams or not, as the Hulu app continues to work on those as well, but has the older (better) UI. It's kinda broken on certain elements and you have to use search to find shows that refuse to display on it, but it still works.
Just because an app is 'unsupported' does not mean it won't still connect and play content. I use tons of very old apps to keep the UI I am more fond of alive. They probably use the same servers so killing the server would end all apps not just old ones.