Eligibility Notice was mailed

[Paddy Sanjeevi]

We filed Green card processing in Oct 20 for primary and dependents in EB3 (I-140 and I-485).  Our priority date was 02-APR-2012. In Jan 22, interfiled to EB2.  Primary got GC Jul 22, but dependents were not.  Now in EB3, dependents are eligible to get GC since the priority date is current.  Dependents have both EAD and Advance Parole.  Since primary was approved in EB2, dependents also being considered in EB2.  Now we got the communication from USCIS like below.

"we mailed you a notice informing you that you are eligible for Form I-485, Application to Register Permanent Residence or Adjust Status, Receipt Number SRC21900 XXXXX.

What does it mean ? We have already applied I-485.

Could you please share more details ?  Appreciate very much

Regards

Paddu