How to upgrade Magento to a newer preview version
Varien would like to note that we do not support any upgrade functionality until the stable version of Magento is released. We recommend to make a fresh installation after every new version release. We cannot guarantee that any customization done on the preview version will work for the stable version.
How will it work in Magento 1.0?
Module and package management is in the works. After the module distribution engine will be finalized it will provide web admin interface for upgrades and adding new modules/packages.
All your modifications will be made as a local module that overrides existing modules functionality.
You would not touch nor overwrite existing code, so that future updates are possible. In the configuration of your customization module, you would specify which models, blocks, controllers, templates, etc. you will replace or extend.
Still want to upgrade your preview version? This is how it should be done now
In case and despite of the things mentioned above you still want to upgrade to the next beta preview version but avoid reinstalling it completely, do the following:
- Backup your database
- Backup all the code you modified yourself, don't forget to keep the original installation archive
- Take care of saving media directory that contains all the uploaded product/category images
- Create a backup copy of app/etc/local.xml file
- Extract and upload all the files it contains to your server
- Delete var/cache and var/session directories
- Point your browser to any Magento page
- Database upgrades should happen automatically
* All the module versions are stored in `core_resource` table per module, and if these versions are lower than ones in the code, Magento will look for these update files and apply them, updating current version of modules in the database. Every time configuration cache is created it is validating the version of db structure for each module against the value in configuration. If it differs it runs necessary upgrade files.
What may be affected ?
Check for the data you had before in your installation. Pay close attention to system configuration settings and the features announced to be changed in the new release.
Then review the files you have changed yourself and put any required changes in the updated installation.
It cannot be emphasized enough that until the stable version release the only recommended way to upgrade to a newer version is to make a fresh install.
We will look into adding module/package managent by the end of the year. A lot of documentation on upgrade process will be available as well.