HA-Proxy version 1.5.18 2016/05/10

is there a way to update it to the latest?

mentax: I don't believe there is anything special about the HAproxy included in the Kazoo repos---you should be able to use any version or even something else like Nginx in place of it if you want. Note that I think there were some config changes between HAProxy 1.x and v2.x, so make sure your config is correct for the version you decide to use.