Boeing has decided to drop the hybrid laminar flow control (HLFC) drag reduction system from the 777X and may even review its future use on the stretched 787 derivatives. The company, which developed the system initially for the 787-9, says the drag benefits do not justify its inclusion on the 777X which is due to achieve firm configuration later this summer. The system has been under consideration for the 777X since the start of the program and at one stage was considered such a certainty ...
That's from 2015, don't know if it's still valid...