There are only 20 episodes in Season 1 according to the following sources, not 21 like listed on Trakt:
http://gb.imdb.com/title/tt4016454/episodes?season=1&ref_=tt_eps_sn_1https://en.wikipedia.org/wiki/Supergirl_(TV_series)
Cleaned it up. In the future, please open a support.trakt.tv ticket since we don't check comments for data update.
1x21 is back for more… I verified TVDB's listing, and initiated a data refresh here. If it doesn't clear up soon I'll open a ticket.
Shout by DanBlockedParent2016-04-22T21:17:23Z
There are only 20 episodes in Season 1 according to the following sources, not 21 like listed on Trakt:
http://gb.imdb.com/title/tt4016454/episodes?season=1&ref_=tt_eps_sn_1
https://en.wikipedia.org/wiki/Supergirl_(TV_series)