jakubas

<a href="http://www.ism-soft.com/tools/wp-picture-calendar-plugin" rel="nofollow ugc">WP Picture Calendar</a> is a wordpress plugin that allows you to add new widget to Your sidebar. 
WP Picture Calendar shows a simple image calendar of World Days whith date and short description. With WP Picture Calendar you will not miss World Day anymore.
Description:
<ol>
<li>All of the photograph link (nofallow) to the relevant Wordl Day pages , so anyone interested can learn more about the World Day shown. </li>
<li>Photo is described by a two-line description under the photo.</li>
<li>Plugin adds the contents with the best practices of SEO. </li>
<li>Widget shows current World Day or countdown to the next random World Day.</li>
</ol>
Demo :
You can see a demo on my website : <a href="http://jakubas.net.pl/test/" rel="nofollow ugc">Jakubas.net.pl</a>

WP Picture Calendar

WP Picture Calendar shows a simple image calendar of World Days whith short description on Your sidebar.

Geoffrey

This plugin adds a message before or after (or both) your post content when this post is outdated. 
You visitor knows when a post is a little bit outdated and reads the content keeping its age in mind.
Features
<ul>
<li>Choose the place where the message is displayed (before or after the content, or both)</li>
<li>Choose which type of posts that are concerned</li>
<li>Custom delay for each post</li>
<li>Hide the message for a specific post (directly from the edition page)</li>
<li>Shortcode and template function</li>
<li>Lots of hooks (for developers)</li>
</ul>
A full documentation is coming.
If you find a bug, please, <a href="https://wordpress.org/support/plugin/juiz-outdated-post-message" rel="ugc">tell me</a>!
You want to translate this plugin and have your name in this page? Find translation files <a href="https://plugins.svn.wordpress.org/juiz-outdated-post-message/trunk/languages/" rel="nofollow ugc">here</a>.

Juiz Outdated Post Message

Simple to integrate, best practice for bloggers ! This plugin is on my toplist ! :)



Nice feature and easy to use

I've already said that to a lot of people, this one is a MUST HAVE.



great idea, UX topissimo

Works like a charm! 

If you want to use the shortcode in your template, do it like this : 
<?php echo do_shortcode('[outdated]'); ?>

Works with WP 4.7.x

This plugin adds a message before or after your post content when this post is outdated

WP Picture Calendar vs Juiz Outdated Post Message