Probably sometime within the next couple of months, though unless you desperately need features on the X299 platform or already have an X299 board it's probably not worth it. It's only 8 cores and 16 threads, you may be better off getting the 9900k instead if you really want to stick with Intel, or look at a Threadripper chip if you really need lots of cores and threads. Even if you insist on X299, it's pretty much going to be the same as the 7820X, just with slightly better out of the box clockspeeds.