Deploying lisp based image applications

I was thinking of deploying a lisp based application(clisp guys). Anyway, if you have an image setup and you have the executable lisp interpreter and have it load the image on startup. Let us say that you want to upgrade some of the functions in the original image, because of bugs or whatever. Could you in theory override the functions in the previous image by loading new scripts or possibly another image.

What is the best way to write pluggable software in lisp.

Has this worked for anyone?
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