The album includes the theme song to the film Koizora, which stars Aragaki herself.[2] It was released in two formats: CD+DVD standard edition and a limited edition which has an illustration cover drawn by Aragaki herself and comes priced at 1,890 yen.[3] The standard edition DVD includes the music video and making of footage of "Heavenly Days".[3]
Sora debuted on the daily Oricon albums chart at #2 with 11,499 copies sold.[4][5] It peaked at #3 on the weekly charts with 72,879 copies sold, making Aragaki the first actress-turned-singer in four years (since Kou Shibasaki) to have her debut album open in the top 3.[6][7]Sora was the 10th best selling album for the month of December 2007.[8] It was 160th (2007) and 167th (2008) on the yearly Oricon albums chart.[9][10]