Redirect new members and existing members that changes their existing level back to the referring page after checkout.

my-pmpro-redirect-to-referring-page-after-checkout.php

<?php
/**
 * Display the last visited non-PMPro page in the confirmation message, OR
 * redirect the member back to the last visited page.
 *
 * Usage Guide:
 *
 * 1. Set your preference to either display the link or redirect back to
 *    the referrer page by setting the $toggle_display_redirect variable
 *    to true or false.
 * 2. Customize your message for the confirmation page in the $referrer_message
 *    variable.
 *
 * This recipe requires that the "Message for Logged-out Users" and
 * "Message for Logged-in Non-members" setting on the
 * Advanced Settings page (Memberships > Settings > Advanced) has
 * "?redirect_to=!!referrer!!" after the !!levels_page_url!! placeholder.
 *
 * E.g <a href="!!levels_page_url!!?redirect_to=!!referrer!!">Join Now</a>, or
 * <a href="!!login_url!!?redirect_to=!!referrer!!">Login</a> <a href="!!levels_page_url!!?redirect_to=!!referrer!!">Join Now</a>
 *
 * 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/
 */

/**
 * This is the place you will set what kind of redirect to use.
 *
 * @return string The kind of redirect to use.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_type() {
	/*
	 * Set this to 'redirect' if you would like redirect on order confirmation,
	 * or set this to 'message' if you want to show the last URL in the confirmation message.
	 */
	return 'redirect';
}

/**
 * This is the place you will set confirmation message you want to show (if type is 'message').
 *
 * @return string The last visited message to show.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_last_visited_message() {
	// translators: %s: The linked URL of the last visited page.
	return esc_html__( 'View your last visited page here: %s.', 'pmpro-customizations' );
}

/**
 * Add last page link to confirmation page text.
 *
 * @param string $message The confirmation message.
 *
 * @return string The updated confirmation message.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_message( $message ) {
	$last_url = my_pmpro_redirect_to_referring_page_after_checkout_get_safe_url();

	// Check if we have a safe last URL.
	if ( null === $last_url ) {
		return $message;
	}

	$last_visited_message = my_pmpro_redirect_to_referring_page_after_checkout_last_visited_message();
	$last_visited_link    = sprintf( '<a href="%1$s">%2$s</a>', esc_url( $last_url ), esc_html( $last_url ) );

	// Append the customized last visited message to the confirmation message.
	$message .= "\n" . '<p> ' . sprintf( $last_visited_message, $last_visited_link ) . '</p>';

	return $message;
}

/**
 * Redirect to last page instead of confirmation page after checkout.
 *
 * @param string $url The confirmation page URL to redirect to.
 *
 * @return string The updated confirmation page URL to redirect to.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_redirect( $url ) {
	$last_url = my_pmpro_redirect_to_referring_page_after_checkout_get_safe_url();

	// Check if we have a safe last URL.
	if ( null === $last_url ) {
		return $url;
	}

	// Send the customer to the last known URL on confirmation.
	return $last_url;
}

/**
 * Store the last URL visited on each page load.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_track() {
	if ( empty( $_REQUEST['redirect_to'] ) ) {
		return;
	}

	$last_url_viewed = $_REQUEST['redirect_to'];

	global $post, $pmpro_pages;

	// Do not track the URL if we are on one of the PMPro pages.
	if ( $post && $pmpro_pages && in_array( strval( url_to_postid( $last_url_viewed ) ), $pmpro_pages, true ) ) {
		return;
	}

	setcookie( 'my_pmpro_last_url_before_checkout', $last_url_viewed, null, '/' );
}

add_action( 'wp', 'my_pmpro_redirect_to_referring_page_after_checkout_track' );

/**
 * Add the filter to the confirmation message or confirmation URL.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_filter() {
	$type = my_pmpro_redirect_to_referring_page_after_checkout_type();

	if ( 'message' === $type ) {
		add_filter( 'pmpro_confirmation_message', 'my_pmpro_redirect_to_referring_page_after_checkout_message', 20 );
	} elseif ( 'redirect' === $type ) {
		add_filter( 'pmpro_confirmation_url', 'my_pmpro_redirect_to_referring_page_after_checkout_redirect' );
	}
}

add_action( 'init', 'my_pmpro_redirect_to_referring_page_after_checkout_filter' );

/**
 * Get the last URL before checkout stored in the cookie.
 *
 * @return null|string The last URL if safe, otherwise null.
 */
function my_pmpro_redirect_to_referring_page_after_checkout_get_safe_url() {
	// Check if there is a last URL stored.
	if ( empty( $_COOKIE['my_pmpro_last_url_before_checkout'] ) ) {
		return null;
	}

	$url = $_COOKIE['my_pmpro_last_url_before_checkout'];

	// Check if the last URL is safe.
	if ( ! wp_http_validate_url( $url ) ) {
		return null;
	}

	return $url;
}

Your code is not work on my website :(

@GiannisRallis This is experimental code that is intended to redirect users back to the last page/post they visited before checking out for membership and is not designed to redirect users to a custom URL per level after checkout.

You should be able to achieve the latter by hooking into the pmpro_confirmation_url filter. Here is a gist that you or your developer may use as an example to tweak to suit your site-specific requirements - https://gist.github.com/ipokkel/c9fb4f9bece3814ffa5120c23a61b811

I hope this helps get you started. :)

Thank you This works for posts but not for custom post types. I am using WP Job Manager and the listings redirect to a subscription page when visited by a non-member. How can I modify these codes to append the referrer to the job listings so that after checkout the user is redirected back to the previous page? Thank you for your help.