Versioning of Extensions?

The GeoPackage Extension Mechanism gives stakeholders a way to add GeoPackage capabilities in a way that minimizes interoperability risks to systems that do not understand the extension. From my perspective, if different implementers are going to implement similar capabilities, then I want them to implement in the same way. That is the whole point of interoperability. The theory is that a client that does not understand an extension will ignore the data. I believe that the extension mechanism is a GeoPackage strength.

The GeoPackage Standards Working Group has two questions for the community:

1. Is the extension mechanism working the way we want it to? Are we getting new capabilities? Are we getting the interoperability we are looking for?
2. What should we do if an OGC-adopted extension has to change? 
• We are leery of adding a "version" column to gpkg_extensions because GeoPackage clients that only understand version 1.2 or prior wouldn't even know about it. It is borderline whether this is a breaking change.
• An alternative that has some backing is to allow extensions to evolve as long as the changes are non-breaking but to force an extension to take a new name if the changes are breaking. 

We would like to get positive answers to these questions because there are a number of initiatives going on that have the potential to add a number of new adopted extensions. Do we need to pivot? I believe the answer is "no" but it is possible I am too close to the situation to make a fair assessment.