Cows Milk for Preemie?

[ZandersMummy0136]

Hi all!
Our LO was born at 28+2 and will be 1 in December. We have been advised to wean him at 6 months actual (3 months corrected) and that has been going great.
We are a little curious as to when to switch to cows milk. Do we use his chronological age or his corrected age?

Thanks!

My DD was born at 31 weeks.

I found all growth and development things were corrected but anything digestive wasn't.

We switched to cows milk at 12 months actual.

I'm not sure what the actual recommended advice is though.