How to securely upgrade from 1.6.x to 1.9.3.1

Question

A customer asked us today if we can update his Magento 1.6.x system.

I'm afraid that it is a little more different then updating from 1.9.x to 1.9.3.1.

What do I need to take care of? Are there any Database upgrades I need to do before? Or can I simply put the new files just on top of the former installation?

Answer 1

Upgrade Roadmap

1. take a backup of current database and current 1.6.x code.
2. download latest magento from the http://www.magentocommerce.com/download
3. remove all folders and files from your 1.6.x code (but you should have backup somewhere) and place all folders and files from the 1.x.
4. now from your 1.6.x merge your following folders into the 1.x
   • Community app/code/community
   • Local app/code/local
   • Media
   • your theme or package (app/design/frontend/default/ or app/design/frontend/)
   • custom folders from Skin (both for adminhtml and frontend).
   • copy your custom xml files from app/etc/modules/ to current app/etc/modules/
   • any custom admin theme folder from adminhtml/default/yourtheme.
   • copy your custom folders from adminhtml/default/default/ (1.6.x) to adminhtml/default/default/ (1.x).
   • custom js files if any from app/js/.
5. now go to app/etc/local.xml.Edit database details their.put your database username and password and database name.
6. now check the site.it done.

Answer 2

I would upgrade to the latest 1.7.x, then latest 1.8.x, then latest 1.9.x. Make sure to backup the database before any upgrades and read any changelogs between versions.

You will also want to make sure the customer has not modified the core files in Magento. If so, those modifications will need to be implemented into custom modules.

After each upgrade you'll want to do very thorough testing to verify things still work. Test as many use cases as possible in as many browsers as possible. After you're done with the upgrades test again to verify everything is still working.

Keep in mind that in 1.9.3, Magento's Adobe Flash based uploader was replaced with an HTML5 based uploader. Please make sure that any custom functionality does not depend on this.