Perhaps the most significant advances for Sony Alpha cameras in 2019 was not the hardware but the firmware. Firmware developments and updates saw updates to Eye AF, the introduction of Animal Eye AF and the introduction of Real Time AF tracking on the new models released and backdated to the A9 camera (replacing the Lock-on AF Focus Areas).
The AF Tracking is now available on the A6100, A6400, A6600, A9, A9II, A7RIV and RX100VII cameras. The Face/ Eye Priority updates were backdated to the A7III and A7RIII cameras as well as the A9.
These changes are outlined in the following two tutorial movies