Platform differences

I have an application which can be built on Gnome Platform 3.30, unfortunately that is end-of-life. The application fails to build on 3.36 or 3.38. It seems they are not backwards compatible. It might help me work out what is causing the failure if I could see a statement of the differences between these versions of the Gnome Platform. Is there some documentation somewhere?

I assume that the only difference between the Freedesktop Platforms and the Gnome ones is that Gnome adds things for the Gnome GUI. I’ve asked whether this is so on the Gnome forum. This wouldn’t cause my build to fail since the module that fails does not use Gnome.

I am guessing that 3.32 and 3.34 were based on different Freedesktop Platforms and something changed in those. How would I find out which Freedesktop Platforms that was and what the change was?

Have had an answer to this question on Gnome Discourse.