PMPro update PayPal Webhook ID value for the new PayPal gateway.

pmpro-update-webhook-id-paypal.php

<?php
/**
 * Adjust the PMPro PayPal gateway webhook ID to point to a new webhook that was manually created.
 * Run this in your browser once yoursite.com/wp-admin/?pp_webhook_id=12345
 * Delete this snippet when no longer needed.
 *
 * Add this code to your site by following this guide - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
add_action( 'admin_init', function() {
	if ( ! isset( $_GET['pp_webhook_id'] ) ) {
		return;
	}

	if ( ! current_user_can( 'manage_options' ) ) {
		wp_die( 'Unauthorized' );
	}

	$environment = get_option( 'pmpro_gateway_environment', 'sandbox' );
	$suffix      = 'sandbox' === $environment ? '_sandbox' : '_live';
	$option_name = 'pmpro_paypal_webhook_id' . $suffix;

	$new_webhook_id = sanitize_text_field( $_GET['pp_webhook_id'] );
	update_option( $option_name, $new_webhook_id );

	wp_die( sprintf(
		'Webhook ID updated. <strong>%s</strong> set to: <code>%s</code>',
		esc_html( $option_name ),
		esc_html( $new_webhook_id )
	) );
} );