[2] The album was promoted by EXID as a 4-member group, since main vocalist Solji was recovering from hyperthyroidism with which she was diagnosed in December 2016.

However, due to member Solji's hyperthyroidism diagnosis, comeback plans were rescheduled for a spring of 2017 release.

An update on member Solji's health confirmed she would extend the halt of her promotions first announced in December 2016.

Eclipse was released at noon KST on April 10, 2017 through several music portals, including Melon and iTunes for the global market.

EXID held their first comeback stage on SBS MTV's The Show on April 11, 2017, performing "Boy" and "Night Rather Than Day".