Changing JMS serialization JSON label names, according to api level

Question

I'm using jms/serializer-bundle with Symfony, and a serialization configuration in YML form, to serialize some Doctrine objects as JSON.

An existing API means that some of the labels were named with underscores (e.g. "created_on")

    createdOn:
        expose: true
        groups:
            label
        serialized_name: created_on

...

    "created_on": "2014-03-06T14:28:17+0000",

but I'd like to tidy this up for a new API version and return responses in camelCase for new API calls.

I had hoped/thought that I could use the JMS Serializer "Until" and "Since" configurations to reference my Entity's properties twice, one with the old serialized_name and one with the new

    createdOn:
        expose: true
        groups:
            label
        serialized_name: created_on
        until: 1.9.x
    createdOn:
        expose: true
        groups:
            label
        serialized_name: createdOn
        since: 2.0

...

    "createdOn": "2014-03-06T14:28:17+0000",

but obviously this does not work. I also tried turning the "2.1" versions into virtual_properties, and using different group names, but I couldn't get that to work either.

If I were using the plain SerializerBuilder/SerializationContext classes then it looks like I could do something like:

$serializer = SerializerBuilder::create();
$serializer->setPropertyNamingStrategy(
    new SerializedNameAnnotationStrategy(
        new CamelCaseNamingStrategy()
    )
);

to force everything to camelCase anyway.

but I'm not. I'm using the jms_serializer service, relying upon its infrastructure to support the serialization groups I need, and I can't see any way through dependency_injection to build my own version of that, which adopts a different naming strategy, for my 'new' API responses.

Has anyone got a way to do this?