It is not uncommon for new posts to contain deprecated code: whilst there may well be good reasons for it in a legacy project, it's usually discouraged in new projects.
Some users no doubt end up here with such deprecated code having followed outdated tutorials, whilst others may end up following posts on SO that contain deprecated code.
How should one respond to:
new questions containing deprecated code;
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?
Existing MSO questions touching on this subject include:
Specifically relates to answers that have become deprecated since they were posted; its accepted answer (of posting a new answer) is not applicable in this case.
Slightly more relevant, but again relates to posts that have become deprecated since they were posted.