Pentaho Data Integration 3.0 migration guide
Introduction
Version 3.0 was re-designed to allow us to gain massive performance gains compared to the 2.x series. Because of this, we had a major API change and many internal changed.
For the most part, transformations and jobs that where created in 2.5 will run without a problem on 3.0.  This document explains where there might be problems and offers solutions.
Please refer to the pages below for the document sections.