Kenney revealed her exit on Twitter Monday when she replied to a fan asking if she'd be writing any episodes in Season 4 (The series was picked up for Season 3 and 4 last year, and production on Season 3 is complete).
"#Voyager (Season 3) will be my last. It was AMAZING experience but time to look 4 new challenges," she wrote, adding, "Outlander fan 4evr, tho!!"
She doesn't have any concrete plans for next steps, but she intends to keep in touch with Outlander's devoted fans. She also promised that Season 4, which is being written now, has some great, "MOSTLY women" writers working on it, so Jamie (Sam Heughan) and Claire (Caitriona Balfe) will be well taken care of.
Kenney had been with the time-traveling romance drama from the beginning. She wrote the acclaimed Season 1 episode "The Wedding," as well as "The Way Out," the third ever episode of the series and the first one not written by showrunner Ronald D. Moore. She's credited with six episodes through the first two seasons and confirmed on Twitter that she wrote the second episode of Season 3, which will air this fall.
Outlander Season 3 premieres in September on Starz.