Why not? We are explicitly told this is the new way things will be going forward (with some allowance for changes based on feedback.) The whole document is geared toward explaining how things will change, and the disclaimer I noted is specifically about telling people "no, you cannot just use old stuff as is, mixed up however you like. If you wish to use the outdated model, you must make these alterations." That's...what using a piece of deprecated software is like. You're not told you can't use it, but the strong implication is that you shouldn't, and if you do, you will be required to modify the formatting to match the updated version. How is that not applicable?