Chinese manufacturer Umeox today unveiled the world's slimmest smartphone - X5. The phone measures only 5.6mm thick. Umexo X5 (dual-core processor, 8-megapixel rear camera, Android 4.2.2 Jelly Bean) has now outperformed the Huawei Acend P6 in terms of thickness and has snatched away the title of the world's slimmest smartphone.