The online class documentation lets me discover what's in the %-packages. I can do this for each of the IRIS versions InterSystems maintain online documentation for. But I haven't found an easy way of being able to tell what changed between versions. To be sure something will be available in the oldest version I want my app to run on I need to always consult that version's class documentation. But then I don't spot new features that I may want to leverage when running on a more recent version.
Perhaps a "Community Opportunity"?
Thank you for submitting the idea. The status has been changed to "Needs review".
Stay tuned!