s invalid.
	 * @throws Waf_Exception If the activation fails.
	 *
	 * @return void
	 */
	public static function activate() {
		Waf_Constants::define_mode();
		if ( ! self::is_allowed_mode( JETPACK_WAF_MODE ) ) {
			throw new Waf_Exception( 'Invalid firewall mode.' );
		}

		$version = get_option( Waf_Rules_Manager::VERSION_OPTION_NAME );
		if ( ! $version ) {
			add_option( Waf_Rules_Manager::VERSION_OPTION_NAME, Waf_Rules_Manager::RULES_VERSION );
		}

		add_option( self::SHARE_DATA_OPTION_NAME, true );

		self::initialize_filesystem();

		Waf_Rules_Manager::generate_automatic_rules();
		Waf_Rules_Manager::generate_ip_rules();
		Waf_Rules_Manager::generate_rules();

		self::create_blocklog_table();
	}

	/**
	 * Ensures that the waf directory is created.
	 *
	 * @throws File_System_Exception If filesystem is unavailable.
	 * @throws File_System_Exception If creating the directory fails.
	 *
	 * @return void
	 */
	public static function initialize_waf_directory() {
		WP_Filesystem();
		Waf_Constants::define_waf_directory();

		global $wp_filesystem;
		if ( ! $wp_filesystem ) {
			throw new File_System_Exception( 'Can not work without the file system being initialized.' );
		}

		if ( ! $wp_filesystem->is_dir( JETPACK_WAF_DIR ) ) {
			if ( ! $wp_filesystem->mkdir( JETPACK_WAF_DIR ) ) {
				throw new File_System_Exception( 'Failed creating WAF file directory: ' . JETPACK_WAF_DIR );
			}
		}
	}

	/**
	 * Create the log table when plugin is activated.
	 *
	 * @return void
	 */
	public static function create_blocklog_table() {
		global $wpdb;

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$sql = "
		CREATE TABLE {$wpdb->prefix}jetpack_waf_blocklog (
			log_id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
			timestamp datetime NOT NULL,
			rule_id BIGINT NOT NULL,
			reason longtext NOT NULL,
			PRIMARY KEY (log_id),
			KEY timestamp (timestamp)
		)
		";

		dbDelta( $sql );
	}

	/**
	 * Deactivates the WAF by deleting the relevant options and emptying rules file.
	 *
	 * @throws File_System_Exception If file writing fails.
	 *
	 * @return void
	 */
	public static function deactivate() {
		delete_option( self::MODE_OPTION_NAME );
		delete_option( Waf_Rules_Manager::VERSION_OPTION_NAME );

		global $wp_filesystem;
		self::initialize_filesystem();

		// If the rules file doesn't exist, there's nothing else to do.
		if ( ! $wp_filesystem->exists( self::get_waf_file_path( Waf_Rules_Manager::RULES_ENTRYPOINT_FILE ) ) ) {
			return;
		}

		// Empty the rules entrypoint file.
		if ( ! $wp_filesystem->put_contents( self::get_waf_file_path( Waf_Rules_Manager::RULES_ENTRYPOINT_FILE ), "<?php\n" ) ) {
			throw new File_System_Exception( 'Failed to empty rules.php file.' );
		}
	}

	/**
	 * Handle updates to the WAF
	 *
	 * @return void
	 */
	public static function update_waf() {
		Waf_Rules_Manager::update_rules_if_changed();

		// Re-generate the standalone bootstrap file on every update
		// TODO: We may consider only doing this when the WAF version changes
		( new Waf_Standalone_Bootstrap() )->generate();
	}

	/**
	 * Check if an automatic rules file is available
	 *
	 * @return bool False if an automatic rules file is not available, true otherwise
	 */
	public static function automatic_rules_available() {
		$automatic_rules_last_updated = get_option( Waf_Rules_Manager::AUTOMATIC_RULES_LAST_UPDATED_OPTION_NAME );

		// If we do not have a automatic rules last updated timestamp cached, return false.
		if ( ! $automatic_rules_last_updated ) {
			return false;
		}

		// Validate that the automatic rules file exists and is not empty.
		global $wp_filesystem;

		try {
			self::initialize_filesystem();
		} catch ( Waf_Exception $e ) {
			return false;
		}

		$automatic_rules_file_contents = $wp_filesystem->get_contents( self::get_waf_file_path( Waf_Rules_Manager::AUTOMATIC_RULES_FILE ) );

		// If the automatic rules file was removed or is now empty, return false.
		if ( ! $automatic_rules_file_contents || "<?php\n" === $automatic_rules_file_contents ) {

			// Delete the automatic rules last updated option.
			delete_option( Waf_Rules_Manager::AUTOMATIC_RULES_LAST_UPDATED_OPTION_NAME );

			$automatic_rules_enabled = get_option( Waf_Rules_Manager::AUTOMATIC_RULES_ENABLED_OPTION_NAME );

			// If automatic rules setting is enabled, disable it.
			if ( $automatic_rules_enabled ) {
				update_option( Waf_Rules_Manager::AUTOMATIC_RULES_ENABLED_OPTION_NAME, false );
			}

			return false;
		}

		return true;
	}
}
<br />
<b>Fatal error</b>:  Uncaught Error: Class &quot;Automattic\Jetpack\Waf\Waf_Runner&quot; not found in /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-waf/src/class-waf-initializer.php:215
Stack trace:
#0 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-includes/class-wp-hook.php(326): Automattic\Jetpack\Waf\Waf_Initializer::remove_module_on_unsupported_environments()
#1 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-includes/plugin.php(205): WP_Hook-&gt;apply_filters()
#2 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-status/src/class-modules.php(311): apply_filters()
#3 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-status/src/class-modules.php(211): Automattic\Jetpack\Modules-&gt;get_available()
#4 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-status/src/class-modules.php(32): Automattic\Jetpack\Modules-&gt;get_active()
#5 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-waf/src/class-brute-force-protection.php(206): Automattic\Jetpack\Modules-&gt;is_active()
#6 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-waf/src/class-brute-force-protection.php(166): Automattic\Jetpack\Waf\Brute_Force_Protection\Brute_Force_Protection::is_enabled()
#7 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-waf/src/class-waf-initializer.php(56): Automattic\Jetpack\Waf\Brute_Force_Protection\Brute_Force_Protection::initialize()
#8 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-config/src/class-config.php(315): Automattic\Jetpack\Waf\Waf_Initializer::init()
#9 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-config/src/class-config.php(217): Automattic\Jetpack\Config-&gt;enable_waf()
#10 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-config/src/class-config.php(149): Automattic\Jetpack\Config-&gt;ensure_feature()
#11 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-includes/class-wp-hook.php(324): Automattic\Jetpack\Config-&gt;on_plugins_loaded()
#12 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-includes/class-wp-hook.php(348): WP_Hook-&gt;apply_filters()
#13 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-includes/plugin.php(517): WP_Hook-&gt;do_action()
#14 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-settings.php(550): do_action()
#15 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-config.php(87): require_once('...')
#16 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-load.php(50): require_once('...')
#17 /var/www/vhosts/casainfotech.co.nz/httpdocs/wp-blog-header.php(13): require_once('...')
#18 /var/www/vhosts/casainfotech.co.nz/httpdocs/index.php(17): require('...')
#19 {main}
  thrown in <b>/var/www/vhosts/casainfotech.co.nz/httpdocs/wp-content/plugins/jetpack/jetpack_vendor/automattic/jetpack-waf/src/class-waf-initializer.php</b> on line <b>215</b><br />