In this video tutorial series Brian Moeskau teaches you how to use the Ext compatibility layer to migrate existing Ext 3 applications to Ext 4. The tutorial covers setup, debugging, dealing with common problems, and techniques for properly updating your application code.
Part 1 focuses on the initial setup of the compatibility layer and getting a demo Ext 3 application running under Ext 4 in compatibility mode.
See Part 1: vimeo.com/23027769
Part 2 builds on the first video, migrating the demo application off of the compatibility layer and getting it fully converted to Ext 4, including using the new class system and dynamic loading.
See the accompanying blog post for more details and to download the Ext 3 to 4 Migration Pack: sencha.com/blog/ext-js-3-to-4-migration