We don’t have any plans to support ISO files right now.
The post @ged_hickman1 linked to above explained our position on the issue when we launched back in 2015, and Brian (our CTO) went into additional detail about this last year. He mentioned that this might happen at some point, but there’s no news to report right now.
It’s worth reading both posts to understand why this format isn’t supported, but if ISO support is a requirement for you, unfortunately I don’t have much more to add here. Note that if you decide Roon isn’t for you, we’ll be happy to process a full refund within the first 30 days of a subscription.
Thanks @Ron_Bhadra!