- new questions containing deprecated code;
This is merely a subset of the vast category of questions asking for help fixing a problem in generally-lousy code. Problems can be as minor as sloppy naming and incorrect brace positioningincorrect brace positioning, and as major as injection vulnerabilities and dangerous or deprecated APIs.
The long-accepted practice here has been to... Answer the questionAnswer the question. The best way to communicate the right way to do something is to demonstrate it solving a problem. Preaching at them while they're struggling isn't going to win you any converts.
- new answers that continue with the deprecated code used in the question, even if the answer is otherwise correct; and
- new answers that introduce deprecated code not found in the question?
Post or up-vote a better answer, down-vote and leave comments noting the problems on the poor answers. For older answers, simply editing to update the codesimply editing to update the code can be a quick and effective solution (be sure to explain WHY in the revision comment though!)
Again, demonstrate the right way to solve the problem, and explain why it's the right way. Bonus points for making the code you're fixing simpler, shorter, and easier to understand while you're at it. Littering up a question with comments stubbornly asserting that something is WRONG without offering a concrete alternative is just annoying.