I know your issue has been discussed over email, but I'm leaving this response for the benefit of anyone else who may be interested!
Unfortunately we no longer actively develop pure PHP APIs for the latest versions of our on-premise products. We do of course still support the older versions in the sense that we will fix any major bugs found.
However, pure PHP can still be used with the latest version via our cloud service.
It is also worth noting that we have made significant recent progress in a Windows build for our PHP C extension: https://51degrees.com/support/docum...extension.
I hope this helps.