According to the cover note of the eighth volume of the complete edition, a sequel to manga “Master Keaton” was announced to be serialized in Big Comic Original magazine from March 19th. The title is “Master Keaton Re Master” and the story will be resumed from 20 years after the end of the previous series.
Nagasaki Takashi, the associate editor of Urasawa, is credited as the story author of the sequel. Katsushika Hokusei, one of the author of the first series, passed away in 2004.
Source: Scan of the cover note