The Samsung Galaxy Note 4 is a cellular smartphone that was released in October 2014. The Galaxy Note 4 Model Number is SM-N910, SM-N910A, SM-N910T, SM-N910V, or SM-N910R4 for American variants.
As per this article, the rollout of the new feature is rather slow, but it should eventually be available for all whatsapp users (at least on supported phones released within the last 10 years or so).