Șerban

On every single post, older than 1 year (365 days), you may add a custom formatted text, in order to let your readers 
know the information included might be outdated.

Old Post Warning

This plugin will display a custom notification on every single post older than 1 year (365 days).

edckwt

** WARNING: DON’T USE THIS PLUGIN IF YOUR PERMALINKS INCLUDE DATES **
Why would you want to do this? Here are a few reasons:
<ol>
<li>New visitors to your site haven’t seen your old content. This will help them discover it.</li>
<li>Old content won’t show up in date-based searches on search engines, but resetting the date can make them look fresh again.</li>
<li>People like to share and link to new content and they determine that by looking at the publication date.</li>
</ol>

Update Posts Date

Update posts date automatically by setting the date to the current date.

Old Post Warning vs Update Posts Date