The Course module modification notification plugin is a local plugin that sends a message to enrolled students any time that course is edited. For example if a new page is added or updated. The message is sent through Moodle’s messaging system and is configurable for those various options (popups when the user logs on, emails, etc.). The messages are sent as a daily digest of changes.
The Mod is maintained by Luke Carrier and is available for Moodle 2.6.
According to the description,
This simple plugin sends users daily digests of changed content within their enrolled courses. As of version 0.2.0, we use the Moodle messaging system to achieve this, allowing your site’s users to choose between the different messaging outputs you’ve enabled (email, Jabber, popup, etc.).
Download it and learn more at https://moodle.org/plugins/view.php?plugin=local_tdmmodnotify