1. A method for wireless communications, comprising: transmitting separate polling messages to poll each of a plurality of apparatuses for channel state information (CSI) feedback, wherein the polling messages are preceded by a sounding message; and in response to the polling messages, receiving CSI feedback from one or more of the polled apparatuses, wherein the CSI feedback comprises an indication of a type of CSI included in the CSI feedback and the type of CSI is multi-user (MU) or single user (SU), and wherein the CSI feedback further comprises an indication of whether the CSI feedback is a full CSI report or a differential CSI report.