GraphQL versioning works differently as the versioning you know from REST. While nothing stops you from versioning a GraphQL API like a REST API, it is not best practice to do so and most often is not needed.

A GraphQL API can evolve. Many changes to a GraphQL Schema are non-breaking changes. You are free to add fields to a type for example. This does not break existing queries.

If you remove fields or change the nullability of a field, the contract with existing queries is broken. In GraphQL it is possible to deprecate fields. You can mark a field as deprecated to signal API consumers that a field is obsolete and will be removed in the future.

public class Query
[Deprecated("Use `persons` field instead")]
public User[] GetUsers() { ... }
public User[] GetPersons() { ... }