Notification icons did not appear on status bar in Oppo F1s
Here i confirmed from Official customer care office of oppo mobiles that recent update of marshmallow in oppo f1s have this issue . and can't be resolved in marshmallow. They suggest me to downgrade your phone back to lolipop 5.1 to remove this issue. So i personally suggest that don't update your oppo f1s to mashmallow .