This attribute was added for supporting several versions of the same objects.
You are right - it doesn’t work for services, but we handle it for enums, exceptions. complex types and arrays.
Mainly usage: client-side.
Client can use several versions of the same _Intf (old and new version).
Each _Intf should have personal namespace.
you can specify used namespaces in the Message.DefaultNameSpaces property so RO SDK will detect rules for serialization/deserialization of specific type.
you can no specify it at all.
this attribute was used in _Intf (i.e. on client side) when you generated CodeFirst-compatible file.
now this attribute (RONamespace) was replaced with ROLibraryAttributes.
a new attribute gives more useful information for cases when CodeFirst service uses items from existing RODLs like DataAbstract4.RODL.