Modifying the NTD of a workspace

[Dave Brosius]

We are developing a set of node type definitions for our application, and as 
is to be expected it is changing over time as we develop it. So far, we have 
just deleted the repository, and started over whenever we make a change to 
the NTD, which is perfectly fine in development. My question is, when 
customers have a repository in place with a defined NTD, and a new version 
of our software is to be shipped, how do we manage the upgrading of data 
from one NTD to another?

Are there any general guidelines for this? Do you have to drop the NTD 
completely, make the changes, then reinstall the new NTD?