USCIS extended the time for petitioners who wants to show their evidence of status from 18 months to 24 months on Sept. 4, 2021. This only applies to petitioners who properly file these two forms:
Form I-751, Petition to Remove Conditions on Residence
or Form I-829, Petition by Investor to Remove Conditions on Permanent Resident Status.

This change is done because there has been an increase in Form I-751 and Form I-829 over the past year.

USCIS will send a receipt notice to the above-mentioned conditional permanent residents that can be presented with their Form I-551, Permanent Resident Card (also known as a Green Card), as evidence of continued status for up to 24 months past the expiration date on their Green Card. Meanwhile, USCIS will keep their cases pending.

Besides, USCIS will send a new receipt notice to eligible conditional permanent residents who properly filed their above-mentioned forms before Sept. 4 and whose cases are still pending. They can use these notices as evidence of continued status for up to 24 months after the expiration date on their Green Card.

For conditional residents who want to stay outside of the United States for a year or more, a reentry permit should be applied. They should file Form I-131, Application for Travel Document before leaving the country.