Migrating to @id and @type for legacy JSON specifications

Are there any best practices on how to deal with the use of different
property names than "@id" (such as "id" or "identifier") and "@type"
(such as "objectType") in addition to not changing them and using
@context for name mapping?

In particular: how could a migration path look like?

Would it be reasonable to use both, the new and the old property, during
a transition?

(The background of the question is a JSON format which has been existing
for several years, is moving to use JSON-LD and will be further
developed within a W3C WG.)

Cheers,
Andreas