Thanks again for that insight. As a software developer myself I can now understand that approach, although, even as Product Manager for a world leading telecomms product, we never took that approach as customers are often very critical and assume, like I did, that what you see is the entirety of the new version.
What I do think is quite clever is that when you switch back to the old version they ask your opinion as to why you are switching back - so then they get to know which of the features are actually being used - that's quite useful intel.
Thanks again.