The Oppo F lineup has been getting two refreshes per year and we are about to see the Oppo F15 come and replace the Oppo F11. The Indian division of the company has just released an official teaser on its YouTube page, showcasing the device and promoting it with the slogan "Flaunt it Your Way". The device also appears briefly in the 30-second clip with a thin pill-shaped oval flash and four snappers, strongly resembling the Oppo A91, launched in China several days ago. If the Oppo F15 is indeed the Oppo A91, then we're looking at a phone with a Helio P70 chipset, 6.4" AMOLED screen...