Pressbooks\Metadata::upgrade PHP Метод

    function upgrade($version)
    {
        if ($version < 1) {
            // Upgrade from version 0 (closed source service) to version 1 (initial open source offering)
            $this->upgradeEcommerce();
            $this->upgradeBookInformation();
            $this->upgradeBook();
        }
        if ($version < 3) {
            $this->upgradeCustomCss();
        }
        if ($version < 4) {
            $this->fixDoubleSlashBug();
        }
        if ($version < 5) {
            $this->changeDefaultBookCover();
        }
        if ($version < 6 || $version < 7) {
            $this->makeThumbnailsForBookCover();
        }
        if ($version < 8) {
            $this->resetLandingPage();
        }
        if ($version < 10) {
            \Pressbooks\Taxonomy::insertTerms();
            flush_rewrite_rules(false);
        }
    }