How to pin songs for download with the IOS player

I finally figured out how to do it on my Android after reading some tips in the forums but there is nothing similar that I can find for features on my iPhone. Does this function not exist for IOS? Also, since we paid for the isub player for iPad/iPhone, do the updates to the player require that we buy it again? My player version is 109 which appears to be old now. Am I missing something?