When Roku unrolls a new major software release, they do it slowly over a few months. Nobody outside of Roku seems to have a clue as to who will get the update when. It will just show up on your device when your number comes up. Take heart, the longer it takes to get to you the more bugs will be quashed, and the more stable it will be.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T