I've installed the free Roku app on my iPhone and my Android tablet. However, there is no free Roku app in my iPad's App Store -- only a bunch of cheesy knock-offs where they try to charge you money any time you hit a button. :cry:
It would be nice to update the Roku app to finally be universal, with native support for the iPad as well. The app has been regularly updated (with Roku OS 8 features for example), and even being optimized for the latest iPhone X display aspect ratio.
Unfortunately the iPad App Store defaults to filtering for native iPad apps only, which hides it from casual searchers.