Routing based on content in body

Hi

We need to route traffic based on a version of our application which is passed in the Body of a request. I know this can be done on version 1.6x as below

    acl redirect_v1   req.body -m reg \"version\"\:\"1\"
    acl redirect_v2   req.body -m reg \"version\"\:\"2\"

However we using Haproxy 1.5.18. Any idea how I can do this with 1.5