A crucial process for world-level mortality statistics is the capability to identify the underlying cause of death from death certificates. Currently such certificates are coded using ICD-10. The selection of the underlying cause is done by means of semi-automated rule-based systems. However, starting from 2022, countries should begin to adopt ICD-11, for which no system is already available. The present paper describes the architecture of a novel system for automated UC selection, with classification-independent rules, and its preliminary validation on two sets of death certificates coded with ICD-10 and ICD-11.