The companies act, 2013

Hi,Sir

We drafted an MOA and AOA as per Companies Act 2013 ...but the incorporation certificate got From MCA is that

Corporate Identity Number : xxxxxxxxxxxxxxxxxxxxxxx( have not mentioned from my side)
I hereby certify that xyz private limited  is this day incorporated under
the Companies Act, 1956 (No. 1 of 1956) and that the company is private limited.

why they have not mentioned that company has been incorporated under companies ACT 2013 instead of 1956

it's confusing me very much......