How to get jelly bean for galaxy s111 +

SAMSUNG GALAXY S2 BLACK IN BOX WITH ALL ACCESSORIES. MINT.
HI ALL I M SELLING MY SAMSUNG GALAXY S2 BLACK. ITS IN MINT CONDITION AND COMES IN BOX WITH ALL ACCESSORIES. ITS LOCKED ON T-MOB. NO PAYPAL AND NO POSTAGE.. ONLY CASH ON COLLECTION.. THANKS.