Here is the official statement:
Due to public health concerns regarding the COVID-19 outbreak, our R&D is affected by the current quarantine policy, resulting in the delayed delivery of system updates. The release of ColorOS 7 trial version for F9 and F9 pro may be postponed.
Our R&D team will speed up the working progress to provide a better user experience to you as soon as possible. We will announce the specific date once it’s decided. Thanks for your continued understanding and support for ColorOS!
Join the Oppo channel on Telegram:
There’s no timeline for the next software update for the Oppo F9 series.
Hi, sorry to have kept you waiting.
Due to public health concerns, our team is affected by the current quarantine policy, which may delay the system updates for F9 and F9 pro.
Our R&D will speed up the progress to provide you a better user experience. Thanks for your support!
— ColorOS (@colorosglobal) April 11, 2020