It would be about on schedule for Sony to roll existing improvements into new versions of the A9 II and A7r Mark IV. Both cameras are due for a refresh, especially the A9 II, which was a very incremental upgrade from the original A9. Rumors now indicate both will see new models in 2022, along with a third new camera about which little is known.
The A7r Mark IV is a rather old body for Sony, having launched 2.5 years ago. If a new model were to come out toward the end of 2022, it would be approaching the 4-year upgrade cadence of the traditional DSLR makers, a trend Sony seems to have been bending toward over time.
The A9 camera came out four years ago, and the Mark II version, which came out two years ago, did improve ergonomics and mechanical shutter frame rate, but offered little else. The same sensor was employed. An A9 Mark III would be welcome among those hoping for a sports shooter costing much less than Sony’s A1 camera it recently released and adopting some of its improvements.
Within a few weeks Canon will have out its EOS R3, which is most comparable to Sony’s A9 series, and will beat it significantly across numerous categories.