-It was the mistake on your parents' green card which should have validity for 10 years, not 2 years. They should have filed I-90 to get the replacement with the validity of 10 years when they get the green card. You need to check their green card to see whether there is a correct category code on their green card. If the green card category code is IR0 or IR5, then it is correct. Otherwise, it is wrong.
我要發什麽表更新綠卡?
-File I-90.
有費用嗎?
-Should have no fee because this was mistake made by USCIS. Explain the mistake in the cover letter, i.e. explain that you were the sponsor to sponsor your father and mother, and their green card category is IR0 (or IR5) which should have the validity of 10 years. You may call USCIS fist to see what they respond.
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