Fixes GiveWP issue with missing firstName

give_upgrades_donor_name.php

<?php

function give_upgrades_donor_name() {
	// Adjust the number in the next line if you have more than 9999 donors
	$donors = Give()->donors->get_donors(['number' => 9999,]);

	if ( $donors ) {

		// Loop through Donors
		foreach ( $donors as $donor ) {

			$donor_name       = explode( ' ', $donor->name, 2 );
			$donor_first_name = Give()->donor_meta->get_meta( $donor->id, '_give_donor_first_name' );
			$donor_last_name  = Give()->donor_meta->get_meta( $donor->id, '_give_donor_last_name' );

			// If first name meta of donor is not created, then create it.
			if ( ! $donor_first_name && isset( $donor_name[0] ) ) {
				Give()->donor_meta->add_meta( $donor->id, '_give_donor_first_name', $donor_name[0] );
			}

			// If last name meta of donor is not created, then create it.
			if ( ! $donor_last_name && isset( $donor_name[1] ) ) {
				Give()->donor_meta->add_meta( $donor->id, '_give_donor_last_name', $donor_name[1] );
			}

			// If Donor is connected with WP User then update user meta.
			if ( $donor->user_id ) {
				if ( isset( $donor_name[0] ) ) {
					update_user_meta( $donor->user_id, 'first_name', $donor_name[0] );
				}
				if ( isset( $donor_name[1] ) ) {
					update_user_meta( $donor->user_id, 'last_name', $donor_name[1] );
				}
			}
		}
	}
}
add_action('init', 'give_upgrades_donor_name');