Theme_Upgrader::delete_old_theme

				$GLOBALS['wp_version'],
				$requires_wp
			);

			return new WP_Error( 'incompatible_wp_required_version', $this->strings['incompatible_archive'], $error );
		}

		$this->new_theme_data = $info;

		return $source;
	}

	/**
	 * Turn on maintenance mode before attempting to upgrade the current theme.
	 *
	 * Hooked to the {@see 'upgrader_pre_install'} filter by Theme_Upgrader::upgrade() and
	 * Theme_Upgrader::bulk_upgrade().
	 *
	 * @since 2.8.0
	 *
	 * @param bool|WP_Error $return Upgrade offer return.