Download music to Iphone for remote listening

Anyone know if Audirvana is planning to update it’s app to download files of offline listening? I’ve installed the app for my Mac and loving the product but I’m looking for something that can also allow me to leave the itunes world entirely. So I’m down to Audirvana and Vox. Vox can do what I’m looking for but I like the performance of Audirvana, not to mention it’s Tidal integration, better.