This annex defines a way to provide encoding information for custom DataTypes. In previous releases of the specification this approach was defined in OPC 10000-3. In OPC 10000-3 a simplified approach is now defined having a DataTypeDefinition Attribute on the DataType Node. The approach using DataTypeDictionaries is provided for backwards compatibility and in case some specific requirements cannot be fulfilled with the simplified approach. It is recommended to only use the approach using the DataTypeDefinition Attribute.