The notice reads:
Dear Roku customer,
Just wanted to let you know that we will perform planned maintenance on August 11 from 5:00am to 11:00am PT.
What this means for you: You can keep streaming on channels you’ve already installed on your Roku device. However, other services such as activating new Roku devices, accessing the Roku Channel Store to add new channels, and making purchases from within certain channels will not be available during this period. We appreciate your patience and apologize for the inconvenience. For more updates, visit support.roku.com.
Roku Customer Care