It is with a great pleasure that the Magento Core Team published a public version of the development Magento 2 and information about it. This new version is still in development and will be available when stability, code quality, features and documentation will be finished. It is expected in one year (end 2012). Lots of lack blamed for version < Magento 2 are going to be history (we hope).
The target of this new version is to provide a better documentation (a complete wiki for store owner, developer, system administrator or designer target public is available and still in progress), an improvement of the performance / security / scalability (EAV still exists), PHPUnit Tests and Automatic Static Code Analysis Tests (including PHP Detector Copy/Paste, PHP Code Sniffer, PHP Mess Detector), easier and better support of multilanguage, etc.
But don’t worry dear Magento 1.x developers, not everything has been changed. At the program, refactoring of some classes, naming convention and templating and skin folders restructuration have been done at the moment. We will see some changes in this first article and how to handle it to upgrade your extensions. Remember, it’s still in development, so the information are there just to keep you informed. I will try to prvovide you up to date information until the official release on this website.
If you are a third party developer, you should follow the recommandations and best practises based on Zend Framework Best Practises and Magento Best Practises (Licenses and category/package/author tags in the docblock of class’ header) to migrate your extensions.
You will find all necessary links about the Magento 2 development version (documentation, svn, tools) at the bottom of this article. But first, I did for you, a resume of the significant changes done between Magento 1.x and 2.x based on the documenation available in the Magento 2 Wiki.