OFFICIAL / Boeing #777X will be certified as part of the 777 family under an amended type certificate. Certification is expected in 2021.
Today, April 29th, the second 777X test aircraft (WH002, N779XX) should perform its first flight. The Boeing Company
Details: https://aeronewsglobal.com/video-boeing-777x-will-be-certified-as-part-of-the-777-family/