PS from Br.414 via "VOJNA POSTA*Br.999*22.6.16" with Serbian censorship "(21) PREGLEDALA/VOJNA CENZURA" (NO.21IV/A, period of use end June 1916 - December 1916) to London. Because of Red Cross endorsement at the upper right, probably was missent to Switzerland and then required a 10c. postage due canc. "GENEVE*9.VIII.16" to send back to London.