This is a reminder for you to keep ALL immigration documents that have been issued for you (e.g., I-20s, DS-2019s, passports) throughout your time in the U.S., even after you extend or change your status, or if you leave the U.S. 

You should keep all of your documents even if you currently have no intention of returning to the U.S. after the completion of your program. If you decide in the future to apply for a benefit, such as permanent residence (green card), you would be required to provide the immigration with all your immigration documentation records. OISS is not required and not able to keep copies of documents indefinitely.  It is your responsibility to keep your own records.