Hextech Chests

did Riot change it so YOU have to get an S, S- or S+ in order to get one? Cause when it first came out I got chests when my teamates got S ranks. But after the last patch. I don't get chests anymore. Its the same with my sister too. She never gets chests anymore. I'm not complaining. I just would like to know how it all works now. :)