From ARRL Web:
A new, speedier, more contest-friendly digital mode is just days away in beta version. WSJT-X Developers say serious work on the new FT4 protocol began shortly after the FT8 Roundup held last December 1-2. The goal was a mode that could compete with RTTY contesting in terms of contact rates, while preserving many of the benefits of FT8. [More]