There's no guarantees; we try to maintain backward compatibility to the best of our ability, and the API existed and was (and is) used internally between MFE products and components of the deployment (like between AHs and ePO server). So most of the time we have to be additive in our work; new parameters or new commands, deprecate old ones, etc. Not doing so would cause ourselves compatibility issues as well.
But sometimes there might be either features or security reasons that dictate modifications to the behavior of commands. Please plan to install & test your scripts in a smaller environment before upgrading your production server.
I am glad to hear that you try to maintain backward compatibiilty to the best of your ability and that most of the time your are additive in your work.
An API is like a promise, and I was hoping for something like the "Stable API and ABI" rules over at libcurl; but I'm glad to know that McAfee is at least thinking about this issue.
I'd like to share the following two articles, which I hope you will share internally:
I especially like the Linus quotes in the second one. Shared.