Chromecast 1 is retired
 

A message on Google's Chromecast firmware support page announced the wind-down of support, saying, "Support for Chromecast (1st gen) has ended, which means these devices no longer receive software or security updates, and Google does not provide technical support for them. Users may notice a degradation in performance." The 1st-gen Chromecast launched in 2013 for $35.

https://fudzilla.com/news/57005-chromecast-1-is-retired