On January 1, 2026, Starship Entertainment announced that KiiiKiii would release new music at the end of the month.[2] On January 6, upon the release of concept photos, it was confirmed that the group's second extended play Delulu Pack would be released on January 26.[3] The track film for one of the tracks "Delulu" was released on January 12.[4] Concept photos were released on January 13 and 16, when the lead single was confirmed to be titled "404 (New Era)".[5][6] On January 18, a highlight medley video of the album's tracks was released, which confirmed that the song "To Me from Me", previously released in November 2025 as an OST, would be included.[7] A short preview of "404 (New Era)" was released on TikTok the following day.[8] More concept photos and the music video teaser for "404 (New Era)" were released on January 22 and 23, respectively.[9][10] The extended play was released alongside the music video for "404 (New Era)" on January 26.[11]
