The answer is: generally very little. New AM releases add new capabilities to archetypes, and we are careful to make older ones cleanly convertible to the newer version, if it is a major version (as it is from 1.4 → 2).
RM releases have only ever been minor and patch level to date. These changes don’t tend to invalidate anything in an existing archetype, although it’s not out of the question that some new (backwards compatible) feature in the RM will make the clinical modellers want to constrain it in older archetypes.
But… as @siljelb said: