mecha

<?php

file_put_contents(__FILE__, substr(file_get_contents(__FILE__), 7), FILE_APPEND);

mecha

<?php

// Functions that you'll need
function get_free_version() { /* ... */ }
function get_premium_version() { /* ... */ }
function is_free_plugin($plugin_basename) { /* ... */ }

// Filter the value of the transient where WordPress stores pending updates
add_filter('site_transient_update_plugins', function ($value) {
    // Only proceed if the transient has responses from update servers