USCIS recently announced that applicants may experience up to an eight week delay in the delivery of their permanent resident card while USCIS is in the process of upgrading its permanent resident card production equipment.
USCIS Field Offices will be issuing temporary evidence of permanent residence in the form of an I-551 stamp to applicants approved for permanent residence at the time of their interview. You will need to take your passport to your appointment. If you do not have a passport, you must bring a passport style photo and government issued photo identification to receive temporary evidence of permanent residence.
If the application is approved subsequent to your interview or by a Service Center or the National Benefit Center, the applicant should bring the above documents to an INFOPASS appointment to be issued temporary evidence of permanent residence in the form of an I-551 stamp.