Which metadata endpoint should I support /$metadata or /EntityDefinitions for CRM development

Hi,

we are working on Dynamics CRM integration development and using Web APIs for the same.

While analyzing CRM I came to know there are 2 endpoint which return metadata and are mentioned below:

1. $metadata (returns EDMX metadata file)

2. /EntityDefinitions and /RelationshipDefinitions (JSON metadata)

I would like to know which endpoint should I consider for developing the CRM ?

Which endpoint is preferred considering the CRM development?

Thanks,