How were you watching Acorn before? I see an AcornTV channel when I search on my Ultra and on the channel store web site. It does indicate it requires a subscription. As to supported devices, their web site is rather lacking in clarity. They only list Roku TV and Roku Stick as supported devices, but I can't see any reason it wouldn't work on all current Roku devices. That said, channel developers can and do enforce limiting their channels to certain devices. BBC is one that only supports a limited number of players, and if you import an unsupported player into the UK, it won't work with the BBC channel.
Here's a link to the help center for AcornTV specifically for Roku devices. Also see this page if your Acorn subscription is through Roku, rather than directly with Acorn.
Dan
Roku Community Streaming Expert
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