Lapone Entertainment released the album in five editions on September 20, 2023, with "Venus" and "Radiovision" serving as the main promotional singles.

Equinox was preceded by two promotional digital singles: "NEWSmile", the theme of the Japanese morning news show Mezamashi 8, and "Gradation", from the film When the Dawn Breaks, I’ll Be the First to See You  [ja], which starred member Ruki Shiroiwa.

The album is also backed by an arena tour titled Beyond the Dark from August to October 2023, with an encore performance in Kyocera Dome Osaka in November.

The theme of the album was said to be "the moment when light and darkness completely confront each other, we break through the boundary between dreams and reality".

[16][17][18] The first promotional single, "NEWSmile", was released as the theme song for the morning news show Mezamashi 8, with music chosen and lyrics written by JO1 members.

[19][20] In an interview with Natalie, Choi Shin-hwa, CEO of Lapone Entertainment, stated that it was a move for the group and company to explore different ways of releasing music.

[24] The Korean version of the song was performed at KCON LA 2023 on August 20, and the music video was released the following day.

[25][23] "Gradation" is the third promotional single from the album and was released on August 31, 2023, as the theme song of the film When the Dawn Breaks, I’ll Be the First to See You  [ja], featuring member Ruki Shiroiwa.

[28] They toured Tokyo, Aichi, Miyagi, Hiroshima, Fukuoka, and Osaka, with a total of 13 shows from August 5 to October 19, 2023.

[24][30] The tour was fully supported by a live band and included exclusive unit performances as well as a camera-approved encore.

[28] The dome concert featured unit songs from the album and air balloons for members to greet the audience in high seats.

[46] The album eventually sold over 263,919 copies by the end of the year and ranked fifteen on Oricon's year-end chart.