Yes, we updated to v3 in master:
I have a simple question about using marshmallow:
Do I need to define new schemas to be used in this plugin for the events, contributions, etc. based on mm.ModelSchema or am I missing something more fundamental?
Yes, define a schema based on
mm.ModelSchema but specify which fields you actually want to include. For anything that has different names or needs extra logic you still need to define Fields directly on the schema.
See e.g. the
AbstractSchema in the Indico core for an example.
Great! This is what I started doing when I had second thoughts.