BCC Activity report email to additional email addresses

pmpro-email-bcc-admin-activity-email.php

<?php
/**
 * BCC additional email addresses on the admin activity email.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpro_email_bcc_admin_activity_email( $headers, $email ) {
	if ( 'admin_activity_email' === $email->template ) {
		$headers[] = 'Bcc:' . 'other1@email.com, other2@email.com, other3@email.com';
	}

	return $headers;
}
add_filter( 'pmpro_email_headers', 'my_pmpro_email_bcc_admin_activity_email', 10, 2 );