I've managed to get this far.
Now it is stuck. Site is down in maintenance mode and I can't log back into admin to try and run it again.
Why or why is it so hard to do anything with Magento? I'm dying a slow death here.
Seems as if others are experiencing same issues - https://community.magento.com/t5/Version-Upgrades-for-2-x/Stuck-during-system-upgrade-2-0-2-gt-2-0-3...
Any suggestions / resolutions ?
Exactly the same problem on my site .
The Magento repositories server sometimes becames frozen. Just rerun the update procedure.
I think you should update Magento with migration tool, which is much easier. For example http://goo.gl/QyT9Gn , it allows to transfer all data with no site downtime. I updated my site within 2 hours with no error.
You can try the following steps in this tutorial. It will help you to make your upgrade successful without any error
Hope you find it useful!
Looks like issue with the php configurations, you may need to provide more memory to the php process. You can look here to increase memory limit http://tutorials.hostucan.net/how-to-increase-php-memory-limit/.
May be you can also take a look at http://goo.gl/XOCkYn . This guide is for migration from magento 1.x to magento 2 but you can look at common issues.
I hope this works for you.
About error of upgrade system upgrade 2.0.2 -> 2.0.4, http://cartmigration.com/?product_cat=shopping-cart-migration. Choose magento to magento migration to upgrade magento database.