by Torsten Landsiedel on WordPress.org
Displays a message at the top of single posts published x years ago or earlier, informing about content that may be outdated.

“The times, they are a-chagin’”: Message on a single post view informing about content that might be outdated.
This simple WordPress plugin displays a message in any single post that has been published x years ago from the current time or earlier. The default time to count back is 1 year. Minimal post age as well as message text, HTML, and CSS are fully customizable via settings.