Description: Letter sent by registered mail from Šibenik to Konak in Serbia. Because there is no postal conection with Serbia, letter was not sent. Accurately franked for second rate of weight. Mixed franking with regular edition and with pair of provosinal stamps for Šibenik. Usage of War contribution is not clear, except if letter were also be sent by express mail. Then the franking will cover said manipulation for first rate of weight. Very interesting for further study. Vertically bent. Photo certificate Petric.