We experience the same problem as in this question/ticket: 'POSbox Currency symbol'
On the POS session's screen, the € symbol is displayed but when printing the ticket a major 'ç' is printed.
Situation changed after upgrading the database to version 12.
My client has exactly the same issue - receipt printer is printing a 'ç' instead of the euro sign. Sometimes it comes out correctly, sometimes not. They are on version 12. I suppose it must be some sort of print driver issue. If anyone has any guidance, that would be great!