iamklaus

Whenever you use wordpress as somekind of a wiki or glossary, there might be some post that you would like to be informed about updates by others. This plugin adds the possibility to decide by each post on the frontend, if you would like to be informed by email if any updates have been on your post of choice.
The email you will receive shows in a comprehensive diff the changes of the old and new version.
<h3>Arbitrary section</h3>
<pre><code><?php code(); // goes in backticks ?>
</code></pre>

NotifyMe

Users can decide on the frontend to receive emails when a particular post has been modified.

AleksHr

If you don’t check your admin panel very often when installing WordPress (perhaps because you prefer to use remote publishing) or want to make sure 
that your clients ‘ WordPress installations are updated, then this plugin is for you. You don’t need to regularly log in to your admin panel, 
subscribe to an RSS feed, or do anything other than install this plugin to receive notifications when WordPress updates, plugins, and themes are released to Telegram messenger.
All you have to do is install the telegram Update Notifier and forget about it until you get a message about the required updates.
To change the Update Notifier Telegram settings, go to the Update Notifier Telegram section in the main settings menu. From there, you can add a unique telegram ID 
that you need to get by writing to the Telegram bot (https://t.me/update_notifier_telegram_bot) . You can also activate update notifications for themes and plugins.

Update Notifier Telegram

Sends notifications to the administrator in Telegram if a new version of WordPress is available. You can also send notifications about available plugi …

NotifyMe vs Update Notifier Telegram