An indication of whether a release file field value can change between two released versions of the same component or reference set member.
- All released versions of the same component or reference set member have the same id (field), but each version has a different effective time (field).
- If a field is mutable (Mutable=YES), its value can differ from one version to the next without changing the identifier.
- If a field is immutable (Mutable=NO), its value must be the same in every version of a component. To change the value associated with an immutable field, the existing component must be inactivated and a new component must be created to replace it. The new component must have a previously unused identifier. The field values are set to replace the inactivated concept with the updated information.
- The mutability for each field, in each type of release file, is indicated in the release file specification table for that component type or reference set.