Three months after the release of the Cyberpunk 2077 Next Gen upgrade which was February 15 so figure it to drop around May 15
It's likely ready right now but they aren't going to step on their main money maker with a free upgrade which should be understandable since they are a business and they need to claw back some of the losses because of the botched Cyberpunk release. Basically it is the profits from Cyberpunk that are allowing them to do this for us and since it is free we really don't have any valid reasons to complain