We decided to keep the old APIs in the code of the api module in 0.23 and remove them only in 0.24. That might allows us to generate old CRDs if needed, keep testing the api-conversion tool etc. But we should not list the fields not supported anymore in the operators it self in the Reference API docs. So we should update the documentation generator to be able to generate the reference APIs only for some API versions.

Created by Strimzi#4631