Most often, final means not only that something is currently the last item in a sequence but also that there will not be any more items in the sequence in the future. However, sometimes people use (misuse?) it to mean merely the last time in the sequence for now.
The generation 1 chromecast is pretty old and underpowered (can't run YouTube TV DRM fast enough apparently) so I wouldn't be surprised, however I can't find anything about it no longer receiving uodates.