Announcement posts on the newsfeed are a different kind of post, reserved for critial company-wide updates.
Announcement posts require a user to actively click an animated icon to dismiss the notification, which in effect acts as an acknowledgement or read receipt.
As a result, the ability to post announcements on the newsfeed should be limited to admin users, or those business leaders who are likely to be sharing crucial updates.
When creating a newsfeed post, the options screen now contains a message to upgrade the post to an announcement. A standard user will see the below message, and will not be able to toggle this announcement on.
To grant access to your admin users to posts announcements, you can use the Admin Application to grant the individual permission.
Remember to save your changes and reserve announcement posts for critical updates. Examples include Product Recalls, Restrictions updates, Furlough notices etc.