Modules should keep working across platform and dependency releases when the APIs they use remain compatible. A version or build-identity difference alone does not establish incompatibility, and identical version numbers cannot make a removed API safe.

The adoption policy, plugin mechanism and compiler lifecycle now state this rule together. The regression tests use real compiled contracts and the real metadata/landing paths. They cover compatible APIs across versions, removed types with unchanged versions, and an incompatible upgrade preserving the working module. The docs also distinguish type checks from member checks and explain why a NodeType bake cache miss normally means recompilation, not a platform hold.