Joe Taylor, K1JT, has released a new version of WSJT-X for download 2.4.0 s mode Q65. This mode should be used for propagation, where the Doppler effect causes frequency fluctuations of more than a few Hz. It is therefore primarily intended for DX connections in higher bands.
Q65 mode uses FSK so 65 tones. A tone for time and frequency synchronization is also included. It is clearly identifiable on the visual representation of the reception spectrum. According to K1JT, the Q65 mode allows to make connections with medium-sized yagi antennas and 100W at 6m regular at a distance of about 2000 km in closed zone.
Documentation and download WSJ-X 2.4.0 can be found at https://physics.princeton.edu/pulsar/k1jt/wsjtx.html