According to latest rumors, next Sony FE lens will be Sony FE 24mm f/1.4 GM lens, to be announced around Photokina 2018 in September.
Polish website Optyczne recently paid a visit to Sony Japan, and had an interview with Sony managers from Sony Japan. According to the interview, Sony currently is developing longer telephoto full frame E-mount mirrorless lenses in the near future. As rumored before, Sony may release FE 135mm lens and FE 400mm lens in 2018.
A source told us that Sony is currently working on several super telephoto prime FE lenses for Sony Alpha full frame mirrorless cameras. Sony is rumored to announce their first full frame professional mirrorless camera next year (Could be named Sony Alpha a9), so release several super telephoto prime lenses are very possible.