Title: Plugin_Upgrader::upgrade
Published: April 25, 2014
Last modified: August 20, 2026

---

# Plugin_Upgrader::upgrade( string $plugin, array $args = array() ): bool|󠀁[WP_Error](https://developer.wordpress.org/reference/classes/wp_error/)󠁿

## In this article

 * [Parameters](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#wp--skip-link--target)

Upgrades a plugin.

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#parameters)󠁿

 `$plugin`stringrequired

Path to the plugin file relative to the plugins directory.

`$args`arrayoptional

Other arguments for upgrading a plugin package.

 * `clear_update_cache` bool
 * Whether to clear the plugin updates cache if successful.
    Default true.

Default:`array()`

## 󠀁[Return](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#return)󠁿

 bool|[WP_Error](https://developer.wordpress.org/reference/classes/wp_error/) True
if the upgrade was successful, false or a [WP_Error](https://developer.wordpress.org/reference/classes/wp_error/)
object otherwise.

## 󠀁[Source](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#source)󠁿

    ```php
    public function upgrade( $plugin, $args = array() ) {
    	$defaults    = array(
    		'clear_update_cache' => true,
    	);
    	$parsed_args = wp_parse_args( $args, $defaults );

    	$this->init();
    	$this->upgrade_strings();

    	$current = get_site_transient( 'update_plugins' );
    	if ( ! isset( $current->response[ $plugin ] ) ) {
    		$this->skin->before();
    		$this->skin->set_result( false );
    		$this->skin->error( 'up_to_date' );
    		$this->skin->after();
    		return false;
    	}

    	// Get the URL to the zip file.
    	$upgrade_data = $current->response[ $plugin ];

    	add_filter( 'upgrader_pre_install', array( $this, 'deactivate_plugin_before_upgrade' ), 10, 2 );
    	add_filter( 'upgrader_pre_install', array( $this, 'active_before' ), 10, 2 );
    	add_filter( 'upgrader_clear_destination', array( $this, 'delete_old_plugin' ), 10, 4 );
    	add_filter( 'upgrader_post_install', array( $this, 'active_after' ), 10, 2 );
    	/*
    	 * There's a Trac ticket to move up the directory for zips which are made a bit differently, useful for non-.org plugins.
    	 * 'source_selection' => array( $this, 'source_selection' ),
    	 */
    	if ( $parsed_args['clear_update_cache'] ) {
    		// Clear cache so wp_update_plugins() knows about the new plugin.
    		add_action( 'upgrader_process_complete', 'wp_clean_plugins_cache', 9, 0 );
    	}

    	$this->run(
    		array(
    			'package'           => $upgrade_data->package,
    			'destination'       => WP_PLUGIN_DIR,
    			'clear_destination' => true,
    			'clear_working'     => true,
    			'hook_extra'        => array(
    				'plugin'      => $plugin,
    				'type'        => 'plugin',
    				'action'      => 'update',
    				'temp_backup' => array(
    					'slug' => dirname( $plugin ),
    					'src'  => WP_PLUGIN_DIR,
    					'dir'  => 'plugins',
    				),
    			),
    		)
    	);

    	// Cleanup our hooks, in case something else does an upgrade on this connection.
    	remove_action( 'upgrader_process_complete', 'wp_clean_plugins_cache', 9 );
    	remove_filter( 'upgrader_pre_install', array( $this, 'deactivate_plugin_before_upgrade' ) );
    	remove_filter( 'upgrader_pre_install', array( $this, 'active_before' ) );
    	remove_filter( 'upgrader_clear_destination', array( $this, 'delete_old_plugin' ) );
    	remove_filter( 'upgrader_post_install', array( $this, 'active_after' ) );

    	if ( ! $this->result || is_wp_error( $this->result ) ) {
    		return $this->result;
    	}

    	// Force refresh of plugin update information.
    	wp_clean_plugins_cache( $parsed_args['clear_update_cache'] );

    	/*
    	 * Ensure any future auto-update failures trigger a failure email by removing
    	 * the last failure notification from the list when plugins update successfully.
    	 */
    	$past_failure_emails = get_option( 'auto_plugin_theme_update_emails', array() );

    	if ( isset( $past_failure_emails[ $plugin ] ) ) {
    		unset( $past_failure_emails[ $plugin ] );
    		update_option( 'auto_plugin_theme_update_emails', $past_failure_emails );
    	}

    	return true;
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-admin/includes/class-plugin-upgrader.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.1/src/wp-admin/includes/class-plugin-upgrader.php#L190)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.1/src/wp-admin/includes/class-plugin-upgrader.php#L190-L269)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#related)󠁿

| Uses | Description | 
| [Plugin_Upgrader::upgrade_strings()](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade_strings/)`wp-admin/includes/class-plugin-upgrader.php` |

Initializes the upgrade strings.

  | 
| [wp_clean_plugins_cache()](https://developer.wordpress.org/reference/functions/wp_clean_plugins_cache/)`wp-admin/includes/plugin.php` |

Clears the plugins cache used by [get_plugins()](https://developer.wordpress.org/reference/functions/get_plugins/) and by default, the plugin updates cache.

  | 
| [remove_action()](https://developer.wordpress.org/reference/functions/remove_action/)`wp-includes/plugin.php` |

Removes a callback function from an action hook.

  | 
| [wp_parse_args()](https://developer.wordpress.org/reference/functions/wp_parse_args/)`wp-includes/functions.php` |

Merges user defined arguments into defaults array.

  | 
| [add_filter()](https://developer.wordpress.org/reference/functions/add_filter/)`wp-includes/plugin.php` |

Adds a callback function to a filter hook.

  | 
| [add_action()](https://developer.wordpress.org/reference/functions/add_action/)`wp-includes/plugin.php` |

Adds a callback function to an action hook.

  | 
| [remove_filter()](https://developer.wordpress.org/reference/functions/remove_filter/)`wp-includes/plugin.php` |

Removes a callback function from a filter hook.

  | 
| [get_site_transient()](https://developer.wordpress.org/reference/functions/get_site_transient/)`wp-includes/option.php` |

Retrieves the value of a site transient.

  | 
| [update_option()](https://developer.wordpress.org/reference/functions/update_option/)`wp-includes/option.php` |

Updates the value of an option that was already added.

  | 
| [get_option()](https://developer.wordpress.org/reference/functions/get_option/)`wp-includes/option.php` |

Retrieves an option value based on an option name.

  | 
| [is_wp_error()](https://developer.wordpress.org/reference/functions/is_wp_error/)`wp-includes/load.php` |

Checks whether the given variable is a WordPress Error.

  |

[Show 8 more](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#)
[Show less](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#)

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/plugin_upgrader/upgrade/?output_format=md#changelog)󠁿

| Version | Description | 
| [3.7.0](https://developer.wordpress.org/reference/since/3.7.0/) | The `$args` parameter was added, making clearing the plugin update cache optional. | 
| [2.8.0](https://developer.wordpress.org/reference/since/2.8.0/) | Introduced. |

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