Model release form for previous work,is there a way to backdate?

[BWVisual]

So i am relatively new to stock,and like many,have harddrives full of photography,i had taken photos of my child back in 2015 onward without doing any sort of model release form at the time,so I'm wondering if it is possible to back date a model release for those dates I took the photos?

Any help appreciated

Thanks

[Abambo]

If your child is at legal age now, the child needs to sign the model release. Else it is recommended to let sign the other parent as you will need the authorization of both parents. And you will need a witness.

I'm not certain if the model release can be legally backdated, however.