The WRF version 3.9 has been released on April 17th, 2017. All updates are given on WRF model page details of UCAR website.
New version of WRF available
Version 3.9 introduce a new hybrid sigma-pressure vertical coordinate. New options for physics, PBL, soil, dynamics and memory requirement imorovements have been made. WRF version 3.9 can use wrfinput and wrfbdy files from version 3.6 to 3.8. WPS makes new treatment of landuse data for land mask and input a new dataset for soil data.
Check our page (in french) about WRF.