Question: When was the album that featured the song "Power" by the group EXO released digitally?

Context articles: Lotto (song)
Power (Exo song)
Lucky One (Exo song)
The War (album)
Heroes (Sabaton album)
Dream (Suzy and Baekhyun song)
Heaven (Depeche Mode song)
Dancing King
Lightsaber (song)
December, 2014 (The Winter's Tale)

"Lotto" is a song recorded by South Korean boy group EXO for the repackaged edition of their third studio album "Ex'Act".
 It was released in Korean and Chinese versions by S.M. Entertainment on August 18, 2016.
"Power" is a song recorded by South Korean boy group EXO for the repackaged edition of their fourth studio album "The War:The Power of Music".
 It was released in Korean and Chinese versions by S.M. Entertainment on September 5, 2017.
"Lucky One" is a song recorded by South Korean boy group EXO for their third studio album "Ex'Act".
 It was released in Korean and Chinese versions by S.M. Entertainment on June 9, 2016 as the first single for the album.
The War is the fourth studio album by South Korean-Chinese boy band EXO.
 It was released digitally on July 18, 2017 and physically on July 19, 2017 by S.M. Entertainment under Genie Music's distribution.
 The album includes a total of nine tracks including the lead single "Ko Ko Bop".
 "The War" received the highest number of pre-orders at that time for a K-pop album, at more than 800,000 physical copies.
 24 days after being released, it became EXO's fourth consecutive studio album to have sold over a million copies.
 The album was re-released under the title The War:" "The Power of Music on September 5, 2017.
Heroes is the seventh studio album by Swedish power metal band Sabaton.
 It was released on 6 May 2014.
 It is the first album to feature the new Sabaton line-up with guitarists Chris Rörland and Thobbe Englund, as well as new drummer Hannes van Dahl.
 It was produced by Peter Tägtgren in Abyss Studios.
 The artwork was made by Péter Sallai and the photos were created by Ryan Garrison.
 The first single "To Hell and Back" from their album was released digitally on 14 March 2014 and available on iTunes, Nuclear Blast, Amazon and Google Play.
 The second single "Resist And Bite" was also released digitally on 2 May 2014, available on iTunes, Nuclear Blast and Amazon.
"Dream" is a song recorded by South Korean singers Suzy and Baekhyun, members of K-pop groups miss A and EXO respectively.
 It was released digitally on January 7 and later physically on January 14, 2016 by Mystic Entertainment.
 Having sold over 1.3 million copies, the song received multiple accolades at major South Korean music award shows in 2016.
"Heaven" is a song by English electronic music band Depeche Mode, released as the lead single from their thirteenth studio album, "Delta Machine" (2013).
 Written by Martin L. Gore and produced by Ben Hillier, the song was world-premiered on KROQ's morning show "Kevin and Bean" on 30 January 2013.
 The single was released digitally in most territories on 31 January 2013, and physically on 1 February.
 In the United Kingdom, "Heaven" was released digitally on 17 March 2013 and physically the following day.
 The B-side "All That's Mine" was written by Dave Gahan and Kurt Uenala.
 An accompanying music video for "Heaven" was directed by Timothy Saccenti and premiered on VEVO on 1 February 2013.
"Dancing King" is a song by South Korean comedian Yoo Jae-suk and South Korean boy group EXO.
 The song is a part of SM Station and is a collaboration single for the variety show "Infinite Challenge".
 It was released digitally on September 17, 2016 by S.M. Entertainment.
"Lightsaber" is a single recorded by South Korean boy group EXO for their collaboration with "Star Wars."
 It was released in Korean version by S.M. Entertainment on November 11, 2015.
 The song was announced to be a bonus track for the group's fourth extended play "Sing for You".
 It was released in both Korean and Chinese on December 10, 2015 along with the extended play.
 The single later was released in Japanese on December 17, 2015 by Avex Trax.
"December, 2014 (The Winter’s Tale)" is a song recorded by South Korean boy group EXO for their live album "".
 It was released in Korean by S.M. Entertainment on December 19, 2014 before the album's release.