Here is the full message from director Yu Suzuki:
Greetings, backers. It’s project director, Yu Suzuki. Today I have something important to announce. I know you are all eagerly anticipating the release of Shenmue III, however, we unfortunately must delay its release. Shenmue III started with you, the project backers. It’s been almost two years since we began this incredible endeavor together. By utilizing new technologies, we have been able to discover new possibilities and expressions. In many ways, the game has become bigger and more beautiful than I initially expected. We do, however, need more time to deliver the game to you. In order to achieve the game concept you supported and my sixteen year-long personal dream, we have revised the development schedule. We are moving ahead with a plan to release the game in the second half of 2018. Details will be revealed in the Backer Report later this month. Thank you very much for your understanding and continued support.
See the message in video form below.