On July 1, SM Entertainment announced NCT's second unit, NCT 127. NCT 127 is based in Seoul, with the number 127 representing the longitude coordinates of Seoul. The unit consists of nine members: Taeyong, Yuta, Jaehyun, Winwin, Mark, Haechan (formerly known as Donghyuck) and later added Johnny, Doyoung, and Jungwoo. On July 7, they had their official debut stage on the music program M Countdown, performing their title track "Fire Truck" and "Once Again" from their album. Their debut EP NCT #127 was released digitally on July 10 and physically on July 11. The 3rd season of NCT Life, which features NCT 127 in Paju.

Furthermore, the repackaged version of the album, NCT #127 Regulate, featuring "Simon Says" was released on November 23 and due to his preparations to debut in NCT's fourth, Chinese unit, WayV, Winwin halted his activities with the unit and didn't participate in the promotions activities for the reissue.