I've just updated my nuvi3597LMT with the latest map update of City Navigator Europe. It shows up in BaseCamp asCity Navigator Europe NTU 2014.40 whilst in Windows Add/Remove Programmes list it's shows as City Navigator Europe (Unicode) 2014.40
In all the updates that I have undertaken in the past few years (Zumo 660 and now the nuvi in addition) I have never seen 'U' given in the map title or even Unicode given in the Windows list. What's it supposed to signify - anyone know?