When registering for the first time with certain bodies in Spain, I was for some reason asked for my passport number rather than my NIE number. I suspect the reason is connected with the reluctance of some official computers to accept NIE numbers without modification (e.g. adding zeros).

Now that I have a replacement passport with a new number, do I have to notify these authorities/companies? To be honest, I doubt if I can remember who they all were! The only problem so far has been when trying to register for computer access, when the original details have to be quoted.