It appears usual that things never work as well as they could.
I was very pleased to receive my digital Temporary Residence Card and it is accepted as proof of my identity whenever it has been required although, the Bulgarian Immigration officials at Burgas airport seemed a little confused by it on both the inward and outward journeys. I think the part that troubles them is that my village has no street names, so it just the village name printed on the card.
However, during the last two weeks the 'card' has let me down. It would appear that the unique numbering system that Bulgarians are required to know by heart is a digit longer (or possible shorter) that the personal I.D. number printed on our 'foreigner' cards therefore, when trying to renew my motor insurance this year, BULSTRAD had gone all computerised this year and of course, their on-line form couldn't handle the missing digit problem. It required a day's delay with calls having to be made to Sofia to get around the problem.
Next problem was when I took a laptop into Burgas for repair and they need to give a computerised receipt; of course, the missing digit caused problems with their computer too until the guy just entered every space with a 9 and it accepted it.
So, I don't expect every computer system to be changed to accept my personal I.D number, but it would appear that perhaps Bulgaria might have put a little more thought into their numbering system for us foreigners.