Ext GWT 2.1 is compatible with GWT 2.0. We have been monitoring the earlier releases of GWT 2.0 to making to ensure the Ext GWT code worked with GWT 2.0.

However, there is one change that you will need to make to use GWT 2.0. See the following post which describes the change you will have to make to run GWT 2.0 with GXT 2.1.

Ext GWT 2.X will continue support for both GWT 1.7 and GWT 2.0. Ext GWT 3.0 will only support GWT 2.0+ and will take advantage of the new features in GWT 2.0.