Using an https save URL

While reading the documentation for the Remote API, I noticed that it says the save URL needs to be a port 80 HTTP url.

Since I didn't want to have the document content sent in the clear, I tried passing an https URL instead and Zoho seemed to accept it and contact our server when saving.

So my question is: is this something that I can rely on, or is it something that works by accident and may break in the future?