Vivo S18 series is set to launch in China on December 14. The company has teased the design and colour options of the upcoming handsets and revealed some key specifications about each of them. Now, more images of the phones have surfaced online that suggest new colour options.Vivo S18 series is set to launch in China on December 14. The company has teased the design and colour options of the upcoming handsets and revealed some key specifications about each of them. Now, more images of the phones have surfaced online that suggest new colour options.