Per the Adult Science Radio official broadcast and the Steins;Gate 10th anniversary official website, the first Steins;Gate 10th anniversary project has been revealed: a Science Adventure concert in Japan.
According to the information provided on the official website, the event will be held on October 12, 2019 at the Zepp DiverCity hall in Tokyo.
Details as to when the next 10th anniversary announcement will take place have not been revealed yet.
UPDATE: Due to the oncoming Typhoon Hagibis, the concert was temporarily cancelled due to safety concerns. It has since been formally rescheduled to January 26, 2020.