以下分享最近申请OPT STEM 24-month extension的时程
先讲结论：现在大多无法在90天内拿到EAD card，本次等待时间为120天。
2/19/2019 Submit OPT extension I-20 application to university
2/26/2019 Receive OPT extension I-20 from university
4/01/2019 OPT extension application sent to USCIS
4/03/2019 OPT application extension received by USCIS
4/08/2019 Receipt issued by USCIS
4/09/2019 Check cashed
以下状态为在官网查到的内容：https://egov.uscis.gov/casestatus/
7/24/2019 We ordered your new card
7/25/2019 We approved your Form I-765
7/29/2019 We mailed your new card for your Form I-765
7/30/2019 The Post Office picked up mail (会提供USPS tracking number)
8/1/2019 收到EAD card