Historically, whenever students and exchange visitors entered the U.S., a Duration of Status (or "D/S") admission allowed them to remain in the U.S. indefinitely as long as they were pursuing a full course of study. Due to a new federal rule, this will change for all students who enter the U.S. on or after September 15. Any student who enters the U.S. on or after September 15 will be subject to the new rule regardless of how many years they may have studied in the U.S. previously.