Yes, we have changed response codes when the old ones were just wrong. Like returning a 500 when really it should be a 404, that kind of stuff. As far as start

Yes, we have changed response codes when the old ones were just wrong. Like returning a 500 when really it should be a 404, that kind of stuff. As far as start/create params, these should not be changed at all, other than that you can pass the options that you could one only pass on start to create. If something has broken here, it was most likely a mistake and should be reported on GH. Even if we change the underlying configuration, we do version the API and make sure we are sending/receiving the same structs over the wire. TLDR; if something broke in the API, please report.