SonyAlphaRumors reports that Sony will finally come out with the A7IV as soon as October, pending logistics issues, and that the camera will possibly have a 33 megapixel sensor.
Sony traditionally releases a revision of the A7 R series with class-leading resolution, and then rolls out a lower-res version a few years later (just how many years is a constant source of speculation and teeth gnashing by Sony shooters). The A7RIV came out two years ago with 61 megapixels.