It marks the first comeback for the group as five members, after the departure of Somin in early November 2015.

[1] On November 9, DSP Media has announced that after long discussions, Somin has made the decision to leave the group.

[1] On November 14, DSP Media posted on April's official instagram account a picture, in the form of a math test, announcing the group's upcoming 1st Single Album.

[6] On November 20, the agency posted pictures from the MV filming and revealed that the song promoted by the group would be called "Muah!".

was posted on the official YouTube channel of the group,[12][13] as well as behind the scenes footage and an interview.