Change the Discount Code text strings if a specific level is in the querystring parameter of the URL #gettext

my-pmpro-discount-code-text-strings.php

<?php
/**
 * This recipe will change the Discount Code text strings if a specific
 * level is specified as a querystring parameter in the URL.
 *
 * 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_discount_code_text_strings_1610643091698( $translated_text, $text, $domain ) {

	// Dont change text if we're not on the level checkout for the AppSumo deal.
	if ( isset( $_REQUEST['level'] ) && 4 != $_REQUEST['level'] ) {
		return $translated_text;
	}
	// Do you have a discount code?
	// Click here to enter your discount code
	switch ( $translated_text ) {
		case 'Discount Code':
			$translated_text = __( 'AppSumo Code', 'paid-memberships-pro' );
			break;
		case 'Do you have a discount code?':
			$translated_text = __( 'Do you have an AppSumo redemption code', 'paid-memberships-pro' );
			break;
		case 'Click here to enter your discount code':
			$translated_text = __( 'Click here to redeem your AppSumo code', 'paid-memberships-pro' );
			break;

	}
	return $translated_text;
}
add_filter( 'gettext', 'my_pmpro_discount_code_text_strings_1610643091698', 20, 3 );