https://arstechnica.com/gadgets/2017/10/roku-releases-five-new-streaming-devices-and-an-os-update/

Roku refreshed its entire streaming device lineup today, updating devices with better processors and other improvements. The company is also rolling out Roku OS 8 to all of the new devices and many older ones. OS 8 adds search and voice control features and brings the over-the-air and over-the-top viewing and searching experiences closer together.

The new devices include the Roku Express, the Roku Express+, the Roku Streaming Stick, the Roku Streaming Stick+, and the Roku Extreme. All were extant products that have simply been refreshed. Gone are the Roku Premiere and Roku Premiere+, which sat in the middle of Roku's lineup last year. The Roku Streaming Stick+ effectively fills the gap.