The change seems to have rolled out in the last few weeks, with
one user on Reddit reporting that casting support was removed on November 10th “with zero warning.” My colleague Dom Preston also found that while he was able to cast to a TV from an older version of the Netflix app, the casting option was no longer available after the app was updated.
Casting support is still available on older Chromecast devices or TVs that support Google Cast natively, according to Netflix’s support page, but only for subscribers on pricier ad-free plans, which start from $17.99 per month. Netflix users with an ad-supported subscription ($7.99 per month) will be unable to cast from their phones even if they own legacy Chromecast devices.