For those unfamiliar with the term, "medieval stasis" is a narrative "rule" that both the Harry Potter and The Lord of the Rings franchises follow to the letter.
The rule states that in any world where magic exists, the highest level of technological development is that of the Middle Ages because magic eliminates the need for technology.
In one of my games, I wanted to break this convention by introducing the concept of "techno-magic." It was simple, and I wonder why no one else does it.