I don't see any official announcement. In my browser's debug console, though, I see plenty of HTTP 400s from a POST to https://comet.api.hbo.com/drm/license/wid

I don't see any official announcement. In my browser's debug console, though, I see plenty of HTTP 400s from a POST to https://comet.api.hbo.com/drm/license/widevine?keygen=playready&drmKeyVersion=2 https://comet.api.hbo.com/drm/license/widevine?keygen=playre... with this as the response body: "Invalid License Request". It would not surprise me if they've intentionally or not changed the supported licensing schemes and invalidated all Linux support without realizing it.