in the last Angular youtube video Minko said they don't plan to keep support for the current structural directives, while they might still keep them for one version deprecated before completely removing them, everything seems to happen quickly

that being said from today RFC summary it doesn't feel it will be ready for v17, so I think they will come in v17.x, then in v18 there will be automated migration and maximum in v19 for the current ones to be removed