Frank Bueltge

Bernhard Kau

Torsten Landsiedel

ChriCo

Caspar Hübinger

Sergej Müller

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 <a href="//wordpress.org/plugins/aged-content-message/faq/" rel="nofollow ugc">fully customizable via settings</a>.
<h4>Languages</h4>
<ul>
<li>English (en_US) (default)</li>
<li>German (de_DE)</li>
<li>Formal German (de_DE_formal)</li>
</ul>

Aged Content Message

This is great little helper! :)

The settings are easy and it does nothing without you configuring it.

If you need more customizations, then you can use filters to further prevent or show the message.

You can style it yourself if you know CSS, but it ships with a generic CSS styling which works in most cases.

Recommended little plugin with a responsive author and a Github repo for issues or PRs. 

Open source can be fun with such great little helper plugins. This is the reason why this directory exists.

Hopefully the "[Discontinued]" text on the Github repo is a mistake ... 

Great little helper - very customizable

Displays a message at the top of single posts published x years ago or earlier, informing about content that may be outdated.

Dreb Bitanghol

This field will provide you more options and flexibility on how you would like to present an instruction or message to your client’s (or site in general) admin interface.
Features:
<ul>
<li>Support PHP.</li>
<li>Option to hide label when field is displayed.</li>
</ul>
Compatible with Advanced Custom Fields:
<ul>
<li>4 (tested up to 4.4.6)</li>
<li>5 (PRO, tested up to 5.3.7)</li>
</ul>
PS: You need <a href="https://wordpress.org/plugins/advanced-custom-fields/" rel="ugc">Advanced Custom Fields</a> installed to use this.
PPS: Even more awesome if you have <a href="http://www.advancedcustomfields.com/pro/" rel="nofollow ugc">Advanced Custom Fields PRO</a> installed.
Important note: Use this with utmost care.

ACF Enhanced Message Field

Exactly what I needed

Exactly what I needed. You could improve the plugin by making the textarea field look more like an IDE, with system fonts, syntax highlights and so on.

Perfect

Awesome!!

Adds an enhanced version of the default Message field to accept PHP and certainly no wpauto().

Aged Content Message vs ACF Enhanced Message Field