It would be even better if this bundle could support both JMSSerializerBundle 0.9 and 1.0.x-dev for now (some people prefer waiting for releases before updating)

I couldn't find right way to determine version of JMSSerializer. Only indirect, such as "if (is_array($type))" or "if ( interface_exists("\JMS\SerializerBundle\Serializer\Handler\SerializationHandlerInterface") )".

Do you think it's good enough to implement it that way?

@iVariable you don't need to check the version IMO. Using is_array($type) is fine IMO. This is how NelmioApiDocBundle implemented it

Any chance to amend and push this through?

Oops, sorry. Have missed previous comment.
@stof is it good enough now?

PS: I preferred to make simple "if" instead of something like getTypeFromOldSerializer and getTypeFromNewSerializer :))

Well, instead of duplicating the whole code of the function (requiring to maintain it twice), it would be easier to normalize the type at the beggining:

if (is_array($type)) {
    // handle JMSSerializerBundle >= 0.10
    $type = $type['name'];
}

// All the existing code here without any modification

Don't you forgot about $type['params'] part?
Now "type" in JMS Metadata is parsed in some way and I don't think it's a good idea to denormalize it back to string. It's not only $type = $type['name']; but a bit more complicated code.

And as for me I think this patch is just a quickfix before maintaining JMSSerializer version 1.0. It'll be better to remove support of old Serializer, after Serializer version 1 release. Don't you think so?