if you haven't enabled an option to scale the video to 1080 in the roku Client then the server will not scale
if you don't have the option in the Client to change scaling then you need to wait for a new version
barring those 2 things the only option left is to re-encode or use a different client/device to play 4k
if you don't have the option in the Client to change scaling then you need to wait for a new version
barring those 2 things the only option left is to re-encode or use a different client/device to play 4k