public static function delayed_init() {
		// TODO Once PUM-Aweber has been updated properly for a few months remove these if checks.
		// TODO Consider adding notice to update aweber.

		self::$disabled = in_array( true, array(
			class_exists( 'PUM_Aweber_Integration' ) && defined( 'PUM_AWEBER_INTEGRATION_VER' ) && version_compare( PUM_AWEBER_INTEGRATION_VER, '1.1.0', '<' ),
			class_exists( 'PUM_MailChimp_Integration' ) && defined( 'PUM_MAILCHIMP_INTEGRATION_VER' ) && PUM_MAILCHIMP_INTEGRATION_VER,
			class_exists( 'PUM_MCI' ) && version_compare( PUM_MCI::$VER, '1.3.0', '<' ),
		) );

		// Checks for single very specific versions.
		if ( self::$disabled ) {
			return;
		}

		require_once Popup_Maker::$DIR . 'includes/functions/newsletter.php';

		do_action( 'pum_newsletter_init' );

		PUM_Shortcode_Subscribe::init();

		add_action( 'wp_ajax_pum_sub_form', array( __CLASS__, 'ajax_request' ) );
		add_action( 'wp_ajax_nopriv_pum_sub_form', array( __CLASS__, 'ajax_request' ) );

		add_filter( 'pum_sub_form_sanitization', array( __CLASS__, 'sanitization' ), 0 );
		add_filter( 'pum_sub_form_validation', array( __CLASS__, 'validation' ), 0, 2 );
		add_action( 'pum_sub_form_success', array( __CLASS__, 'record_submission' ), 0 );
	}