How to add a field to a struct dynamically?

Suppose we have a proxy contract that separates Data layer from Logic layer.
We have a struct in Data contract, like this:

struct person {
    uint id;
    string name;
}
mapping(address => person) persons;

We have deployed this contract and the Dapp users have entered data in it.

Now suppose we want to change the logic contract and add a birth_year field to the struct. how can we make this change to the struct dynamically? Its final form would be as follows:

struct person {
    uint id;
    string name;
    uint birth_year;
}
mapping(address => person) persons;

Even assembly language is acceptable, but sure Solidity is better.