Season 5
Maybe if Nick want to do one more. If not and maybe a movie.
shareJack already confirmed it. He said they were signed for 5 seasons and they were going back to do the rest of season 4 soon. This video was like a month or two ago.
shareBy the time Season 5 is filmed and airing, Jack and Kira are going to be well into their 20's (Jack turned 20 last month), and Diego's probably going to old enough to want to do new things as he gets older (he just turned 15 I believe) so they're probably all going to want to do new projects/shows/movies by the time S5 wraps.
https://www.fanfiction.net/s/11891397/1/Supernatural-Wayward-Sons