Sprint customers won't have to do anything to get the faster speed cap as the change will be "network based". In addition, the carrier does not plan on spreading the word to customers about the increase in the speed cap. Only 4G phones will be affected as Sprint's 4G modems will still be limited to a 1.0 Mbps speed cap.
source: AndroidPolice via AndroidCentral
This internal Sprint communications says that the carrier's 4G upload speed cap will rise 50% on June 10th