There is no behaviour specified regarding subtypes and instances when changing ObjectTypes and VariableTypes. It is Server-dependent, if those changes are reflected on the subtypes and instances of the types. However, all constraints defined for subtypes and instances have to be fulfilled. For example, it is not allowed to add a Property using the ModellingRule Mandatory on a type if instances of this type exist without the Property. In that case, the Server either has to add the Property to all instances of the type or adding the Property on the type has to be rejected.