I worked at medtronic in the early 2000's (early paradigm pumps) and were evaluating wireless protocols and security... at the time we determined it was impossible to secure, once the FDA approved another device maker that did have connectivity there was a scramble to catch up. (this was palmos/pocketpc era). It was fun work but I always remembered how insanely detailed the code was, 8bit low power microcontrollers (some 16bit) but really really really tight C code. Then the demand for remote control happened and that really crapped the bed. https://www.medtronic.com/en-us/e/product-security/security-...

The amazing developer Scott Hanselman built on a PalmOS app to store readings and if I recall correctly wore 2 pumps with fast/slow insulin... he had a cybernetic pancreas in the mid-2000's.