According to a recent filing, work on the TRON Lightcycle Power Run roller coaster at the Magic Kingdom is set to be completed just in time for Walt Disney World’s 50th anniversary in 2021.With construction starting February 6th, 2018, the filing claims the work will be complete by August 16th, 2021 (barring any delays). The attraction should open in Tomorrowland somewhere around that time.
Source: https://wdwnt.com/2018/02/breaking-tron-lightcycle-power-run-opening-date-revealed-magic-kingdom-construction-begins-next-week/