You can use an announcement forum for general news. This special type of forum allows you to share news with all enrollees without giving them the options of replying. This is particularly useful to share information that apply to all learners of the course regardless of their course progress. For example, you can post messages about upcoming live sessions or newly added supplementary material.
To enable it got to Course > settings > Appearance > Number of announcements and select at least 1.
When enabled, it is placed at the top of the course.
In the announcement forum settings, under Subscription and tracking, select auto-subscription. Everyone is subscribed initially but can choose to unsubscribe at any time. Bear in mind that you must give the option to users to unsubscribe and then forcing users to subcribe is not allowed on atingi.