Don’t Let Your Plugin Be Activated on Incompatible Sites

When you write a WordPress plugin, you can specify a minimum WordPress version that your code is compatible with, using the “Requires” option in your plugin header, but it isn’t enforced. Along with that, there’s no way to specify a minimum version of PHP or MySQL.

This can cause your users to have bad experiences with your plugin, and you’ll get bad ratings.

So, here’s how I make sure my plugins are only activated when I want them to be.

//  In this example, only allow activation on WordPress 3.7 or higher
class MyPlugin {
    function __construct() {
        add_action( 'admin_init', array( $this, 'check_version' ) );

        // Don't run anything else in the plugin, if we're on an incompatible WordPress version
        if ( ! self::compatible_version() ) {
            return;
        }
    }

    // The primary sanity check, automatically disable the plugin on activation if it doesn't
    // meet minimum requirements.
    static function activation_check() {
        if ( ! self::compatible_version() ) {
            deactivate_plugins( plugin_basename( __FILE__ ) );
            wp_die( __( 'My Plugin requires WordPress 3.7 or higher!', 'my-plugin' ) );
        }
    }

    // The backup sanity check, in case the plugin is activated in a weird way,
    // or the versions change after activation.
    function check_version() {
        if ( ! self::compatible_version() ) {
            if ( is_plugin_active( plugin_basename( __FILE__ ) ) ) {
                deactivate_plugins( plugin_basename( __FILE__ ) );
                add_action( 'admin_notices', array( $this, 'disabled_notice' ) );
                if ( isset( $_GET['activate'] ) ) {
                    unset( $_GET['activate'] );
                }
            }
        }
    }

    function disabled_notice() {
       echo '<strong>' . esc_html__( 'My Plugin requires WordPress 3.7 or higher!', 'my-plugin' ) . '</strong>';
    }

    static function compatible_version() {
        if ( version_compare( $GLOBALS['wp_version'], '3.7', '<' ) ) {
            return false;
        }

        // Add sanity checks for other version requirements here

        return true;
    }
}

global $myplugin;
$myplugin = new MyPlugin();

register_activation_hook( __FILE__, array( 'MyPlugin', 'activation_check' ) );

It’s only a little extra code when added to a plugin, provides complete protection, and won’t cause any weirdness on the front end of your site, it’ll just deactivate itself either on activation, or when someone visits wp-admin.