Interesting. I am also sure I have output to E7,E17 and HRT Microstreamer from Spotify under ios 5,6&7 in the past. But tonight under 7.2 my ipad is saying "no way". I have just flattened my iPhone's battery so will have to wait until morning to try again.
Edit: after 30 minutes writing replies here Spotify is now behaving as expected so this post is now withdrawn. I haven't moved a single cable so am totally perplexed.
Edited by xeroian - 3/24/15 at 6:31pm