Sony today has registered a new camera code WW119533 in China. According to specs of registered info, this WW119533 camera code is registered by Sony China (Wuxi), similar as previous camera codes: a6600 (WW594724), a6100 (WW642826), RX100 VII (WW246025). So this WW119533 could be a new RX model (RX10 V) or a new APS-C mirrorless camera or an new entry-level full frame mirrorless camera (Sony a5). Stay tuned.
It is not likely this camera code is upcoming Sony a7S III. We expect Sony a7S III will be officially announced in the first half of 2020, most likely at NAB show in April, 2020.