Best practice for extending companion specification

[kristianmo]

Hello, there is a companion specification (CS) with types defined in namespace 2. Instances of each CS type are added in a namespace 3. The variables in the types are all missing the Definition property. Until the companion specification gets an update, what is the best practice for extending/adding Definition or other properties to variables and objects in an CS. 

• Should the types get new optional properties in a new namespace?

• Should the types be left alone and add the new properties to the instances in namespace 3?

• Should the types be left alone and add the new properties to the instances in a new namespace 4?

• Other options?

[opcfoundation-org]

Definition property is only used for DataTypes. Can you clarify?

[kristianmo]

The CS used for instance TwoStateDicreteType for bool in the types. They did not include Definition, or more generally if I need to add MySuperImportantProperty to every variable.

[GoetzGoerisch]

https://reference.opcfoundation.org/Model-Best/v103/docs/11

[kristianmo]

Thanks, if I read this correctly then I can

1. Create subtypes for mandatory additions
2. Extend the types with optional properties
3. Add it to the instances of the types directly

All are acceptable and depends on the use case. But it was a bit vague on the namespace usage, so I assume if I go with option 3 I can use the instance namespace?