My client is running a highly customized version of magento CE 1.4.1.1. I have successfully extricated all of the custom code into local modules and custom themes and installed the changes onto a clean release version of 1.4.1.1.
The magento documentation says the upgrade path is 1.4.1.1->1.7->1.9.x.x but my first attempt to upgrade 1.4.1.1->1.7.0.2 failed. Google searches produced many items that said you should upgrade 1.4.1.1->1.4.2->1.5.0.1->1.6.x....in stepwise fashion until you get to the level you want. Labor intensive for sure, but I was willing to do that.
I was successful in an upgrade to 1.4.2 by doing the following:
* Downloaded and installed a clean version1.4.2 system
* Truncated all log files, and dumped the client's 1.4.1.1 database
* Created a new database and loaded dumped 1.4.1.1 database
* Ran install of 1.4.2 pointing to new database
Tried to repeat the process above to go from 1.4.2.0->1.5.0.1 and got the following error:
a:5:{i:0;s:224:"Error in file: "C:\xampp\htdocs\magento1501\app\code\core\Mage\Sales\sql\sales_setup\mysql4-upgrade-1.4.0.21-1.4.0.22.php" - SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '' for key 'UNQ_INCREMENT_ID'";i:1;s:998:"#0 C:\xampp\htdocs\magento1501\app\code\core\Mage\Core\Model\Resource\Setup.php(390): Mage::exception('Mage_Core', 'Error in file: ...')
I have no idea what to do about this error (but have tried alot of things). Any suggestions? (BTW: the 1.4.1.1->1.7.0.2 gave me a similar error though it might have been in a different module: customer vs. sales).
Help!
