Spotify not connecting through USB to my Sony stereo

[lanabeee]

I updated 60+ apps at once the other day including Spotify, didn't install the iPhone update, now my stereo won't recognise my iPhone as a supported device when connected via USB. I can play via AUX but that means my battery dies & I can't change the song with the remote. I thought it was the stereo until my boyfriend tried his phone (iPhone 6, without the latest Spotify update) & it worked fine just like mine used to two days ago. I want to scream, can anyone help?