Run this sql-query before upgrade via phpMyAdmin.
Do not forget do full backup of your cart (see database export tab in phpMyAdmin)
--
-- DDL for table `user_sessions`
--
DROP TABLE IF EXISTS `abc_user_sessions`;
CREATE TABLE `abc_user_sessions` (
`user_id` int(11) NOT NULL,
`token` varchar(128) NOT NULL DEFAULT '',
`ip` varchar(50) NOT NULL DEFAULT '',
`last_active` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`date_added` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`user_id`, `token`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
--
-- DDL for table `customer_sessions`
--
DROP TABLE IF EXISTS `abc_customer_sessions`;
CREATE TABLE `abc_customer_sessions` (
`customer_id` int(11) NOT NULL AUTO_INCREMENT,
`session_id` varchar(128) NULL DEFAULT '',
`ip` varchar(50) NOT NULL DEFAULT '',
`last_active` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`date_added` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`customer_id`, `session_id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
#update menu design item
UPDATE `abc_dataset_values`
SET value_varchar = 'design/template'
WHERE row_id=3 AND value_varchar='extension/extensions/template';
#fix or prior upgrade 1.3.4->1.4.0
UPDATE `abc_blocks`
SET controller='blocks/viewed_products'
WHERE controller='viewed_products/viewed_products' AND block_txt_id = 'viewed_products';