64 ](https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-admin/includes/class-plugin-upgrader.php#L564-L586)

  * method  [ Plugin_Upgrader::delete_old_plugin() ](https://developer.wordpress.org/reference/classes/plugin_upgrader/delete_old_plugin/)

Deletes the old plugin during an upgrade.

Used by [ 0 functions ](https://developer.wordpress.org/reference/classes/plugin_upgrader/delete_old_plugin/#used-by) | Uses [ 3 functions ](https://developer.wordpress.org/reference/classes/plugin_upgrader/delete_old_plugin/#uses) | Source: [ wp-admin/includes/class-plugin-upgrader.php:677 ](https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-admin/includes/class-plugin-upgrader.php#L677-L711)

  * class  [ Theme_Upgrader ](https://developer.wordpress.org/reference/classes/theme_upgrader/)

Core class used for upgrading/installing themes.

Used by [ 0 functions ](https://developer.wordpress.org/reference/classes/theme_upgrader/#used-by) | Uses [ 1 function ](https://developer.wordpress.org/reference/classes/theme_upgrader/#uses) | Source: [ wp-admin/includes/class-theme-upgrader.php:21 ](https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-admin/includes/class-theme-upgrader.php#L21-L807)

  * method  [ Theme_Upgrader::upgrade_strings() ](https://developer.wordpress.org/reference/classes/theme_upgrader/upgrade_strings/)

Initializes the upgrade strings.

Used by [ 2 functions ](https://developer.wordpress.org/reference/classes/theme_upgrader/upgrade_strings/#used-by) | Uses [ 1 function ](https://developer.wordpress.org/reference/classes/theme_upgrader/upgrade_strings/#uses) | Source: [ wp-admin/includes/class-theme-upgrader.php:55 ](https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-admin/includes/class-theme-upgrader.php#L55-L65)

  * method  [ Theme_Upgrader::install_strings() ](https://developer.wordpress.org/reference/classes/theme_upgrader/install_strings/)

Initializes the installation strings.

Used by [ 1 function ](https://developer.wordpress.org/reference/classes/theme_upgrader/install_strings/#used-by) | Uses [ 1 function ](https://developer.wordpress.org/reference/classes/theme_upgrader/install_strings/#uses) | Source: [ wp-admin/includes/class-theme-upgrader.php:72 ](https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-admin/includes/class-theme-upgrader.php#L72-L110)

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