New Immigrant parents awaiting Green card after entering USA

[MSPdesi]

My parents entered USA as new immigrants . It has been more than 8 months and they are yet to receive the physical green card mailed to them.
Is there anybody in the same boat who are awaiting green card to be mailed ? Also the I-551 stamp will expire in 4 months. Any suggestions whether my parents can stay legally in US after the expiry of I-551 stamp as we are still waiting for green card to be mailed. We get standard response by USCIS that the avg wait is 4 months to mail the green card.

[newacct]

They are permanent residents, and remain in legal status indefinitely, even if they have no card. I think what you are describing is not an "I-551 stamp", but rather the fact that their immigrant visa turns into an I-551 for one year after entry, and that one year ends in 4 months. They can always go into a USCIS office to get an actual "I-551 stamp" on their passport if they need proof of permanent residency while waiting for their card.