Restrict a membership level to no longer allow sign ups after a given date (limited time offer) using Paid Memberships pro

pmpro-limited-time-registration.php

<?php
/* Checks to see if a registration is happening after a given date; if so, prevent registration and stop new signups for the level/no longer display the level on the levels page
*/

global $pmproml_end_date, $pmproml_limited_level_id;
$pmproml_limited_level_id = 1; // change to the ID of the limited-time membership level
$pmproml_end_date = "2019/04/30"; // change to the date registration ends, in YYYY/MM/DD format

function pmproml_pmpro_registration_date_checks( $value ) {
	global $wpdb, $pmproml_end_date, $pmproml_limited_level_id;

	$level_id = intval( $_REQUEST['level'] );
	$date_format = "Y/m/d";
	$registration_date = date($date_format);
	$limited_level = pmpro_getLevel( $pmproml_limited_level_id );
	
	if( $registration_date >= $pmproml_end_date && $pmproml_limited_level_id == $level_id  ) {
		global $pmpro_msg, $pmpro_msgt;
		$pmpro_msg = __( "Memberships for this level are no longer available as of $pmproml_end_date", 'paid-memberships-pro' );
		$pmpro_msgt = "pmpro_error";
		$wpdb->update(
				$wpdb->pmpro_membership_levels,
				array(
					'allow_signups' => 0
				),
			array(
			'id' => $level_id
			)
		);
		$value = false;
	}
	return $value;
}
add_filter( 'pmpro_registration_checks', 'pmproml_pmpro_registration_date_checks', 10, 1 );

function pmproml_pmpro_hide_limited_levels( $pmpro_levels ) {
	global $wpdb, $pmproml_end_date, $pmproml_limited_level_id;

	$date_format = "Y/m/d";
	$registration_date = date($date_format);
	$limited_level = pmpro_getLevel( $pmproml_limited_level_id );

	if( $registration_date >= $pmproml_end_date && isset( $limited_level->allow_signups ) && $limited_level->allow_signups != 0 ) {
		$wpdb->update(
			$wpdb->pmpro_membership_levels,
			array(
				'allow_signups' => 0
			),
			array(
			'id' => $pmproml_limited_level_id
			)
		);
	}
	return $pmpro_levels;
}

add_filter('pmpro_levels_array', 'pmproml_pmpro_hide_limited_levels', 10, 1);

This recipe is included in the blog post on "Offer a Membership Level for a Limited Time" at Paid Memberships Pro here: https://www.paidmembershipspro.com/offer-a-membership-level-for-a-limited-time/