Hi,
Can you please check your database using "PHPMyAdmin".
The table "leca0_users" should be in collation "utf8_general_ci" but it looks like regarding your error message that the table (or just the field) is in "latin1" collation.
The problem you have is not with the upgrading from Essential to Business but the update from 2.3.3 to 2.3.4.
You can fix the problem by editing the file "administrator/components/com_hikashop/views/order/view.html.php" and replace
$database->setQuery('SELECT a.*,b.*,c.*,IFNULL(c.name COLLATE utf8_general_ci,CONCAT_WS(\' \',d.address_firstname,d.address_middle_name,d.address_lastname)) AS hikashop_name '.$query,(int)$pageInfo->limit->start,(int)$pageInfo->limit->value);
By
$database->setQuery('SELECT a.*,b.*,c.*,IFNULL(c.name,CONCAT_WS(\' \',d.address_firstname,d.address_middle_name,d.address_lastname)) AS hikashop_name '.$query,(int)$pageInfo->limit->start,(int)$pageInfo->limit->value);
I will report your issue to Nicolas who submit the fix during September.
Regards,