Error when sending a response to a request using the API call "sendReply"

Error when sending a response to a request using the API call "sendReply"

Hello,
I am using this ManageEngine Support center plus API to manage requests through a C# project. I am following this link below for documentation. 

The problem I am facing is that when I try to reply to a request, using    the "sendReply" API call,  I get the following error message :" The API has been changed for this feature. Please update your app."
How do I get the updated version of this feature ? and Is there another link that I can follow for the updated API?
Any help is much appreciated.
Thanks.
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