+
+// Do it. No output.
+if ( 'upgrade_db' === $step ) {
+ wp_upgrade();
+ die( '0' );
+}
+
+/**
+ * @global string $wp_version
+ * @global string $required_php_version
+ * @global string $required_mysql_version
+ * @global wpdb $wpdb
+ */
+global $wp_version, $required_php_version, $required_mysql_version;
+
+$step = (int) $step;
+
+$php_version = phpversion();
+$mysql_version = $wpdb->db_version();
+$php_compat = version_compare( $php_version, $required_php_version, '>=' );
+if ( file_exists( WP_CONTENT_DIR . '/db.php' ) && empty( $wpdb->is_mysql ) )
+ $mysql_compat = true;
+else
+ $mysql_compat = version_compare( $mysql_version, $required_mysql_version, '>=' );
+
+@header( 'Content-Type: ' . get_option( 'html_type' ) . '; charset=' . get_option( 'blog_charset' ) );