Android 9.0 Pie has just arrived, and Vivo is one of the first brands to reveal its update plans. According to the Chinese company, its handsets will get the update in Q4 2018. Insiders familiar with the matter claim that the Vivo X21 will probably be the first one to get the update.
https://www.notebookcheck.net/Android-Pie-coming-to-Vivo-handsets-in-Q4-X21-apparently-the-first-on-the-list.321196.0.html