Federated learning: Can I train using a histogram representation of data?

Hello, I’m trying to aggregate some models for federated learning of a xgboost regressor. I managed to get an aggregated histogram representation of features and it’s gradients, but can I use this data to train the model given that I have the gradient and hessians? or is it not possible to re-use this data?

You can try the custom boost function by passing your gradients and hessians: