gp-nested-forms-copy-parent-entry-props-to-child.php

<?php
/**
 * Gravity Perks // Nested Forms // Copy Parent Entry Properties on Parent Form Submission
 * http://gravitywiz.com/documentation/gravity-forms-nested-forms/
 */
// Update "123" to your parent form ID.
add_action( 'gform_entry_created_123', function( $entry, $form ) {

	// Specify which properties you would like to populate from the parent.
	// Supports: id, form_id, post_id, date_created, is_starred, is_read, ip, source_url, user_agent, currency, payment_status, payment_date, payment_amount, payment_method, transaction_id, is_fulfilled, created_by, transaction_type, status, date_updated, last_payment_date
	$copy_from_parent = array( 'transaction_id', 'payment_date', 'payment_status' );

	// Specify the field ID of the Nested Form field on your parent form.
	$nested_form_field_id = 1;

	$child_entry_ids = explode( ',', rgar( $entry, $nested_form_field_id ) );
	foreach( $child_entry_ids as $child_entry_id ) {
		foreach( $copy_from_parent as $parent_property ) {
			GFAPI::update_entry_property( $child_entry_id, $parent_property, $entry[ $parent_property ] );
		}
	}

} );

is this page still valid ??? if so how could i use it?

@SerpikoIT I haven't tested this since I originally wrote it, but it appears functional. To use this, copy and paste the snippet into your theme's functions.php file and update the form and field IDs as indicated via the inline comments.