5x supports CIQ 3.0 and there is support of music: Music – In CIQ v3.0, we have opened the audio/music APIs so any third party can create and upload an audio or a music app to the CIQ app store. It means that it is not valid for 5x, although it supports CIQ 3.0?
CIQ3 allows writing music provider apps but ONLY for devices that support music. The plus devices, the 645m (not the 645) the va3m (not the va3) and the D2 Delta devices (when they get CIQ3).