2 Mails from Uscis 4 months after Oath of ceremony

[Joe11223344]

God an alert from USPS that uscis sent me 2
mails, I thought I was done with uscis since I did my Oath in October, and I’ve the certificate.
Does anyone know what this can be again?

[stuff2447]

Did you receive the letters? What were they for?

[ShibuM]

Call USCIS and ask them