How should an old API version be deprecated gracefully?

When researching and reading about the WP REST API utilization I’ve seen many topics mentioned about how another version should be rolled out but nothing in the documentation regarding a return for a deprecated version. Planning the life span of an API and how I should develop for each version I was unsure how I should fire a return indicating a newer version is pushed.

For example:

add_action( 'rest_api_init', function () {
  register_rest_route( 'cpt/v1', '/all_posts/', array(
    'methods' => 'GET',
    'callback' => 'some_cpt',
  ) );
} );

if I were to change the route to:

add_action( 'rest_api_init', function () {
  register_rest_route( 'cpt/v2', '/all_posts/', array(
    'methods' => 'GET',
    'callback' => 'some_cpt',
  ) );
} );

what should I properly pass through v1 to indicate there is a new version? Was thinking of using WP_Error as it is shown but I’m unsure the code return and where to implement the WP_Error:

return new WP_Error( 'new_version_needed', 'Deprecated version', array( 'status' => 303 ) );

or:

return new WP_Error( 'new_version_needed', 'Deprecated version', array( 'status' => 410 ) );