Notifications center of Bitrix24 Messenger shows you notifications about new messages, new tasks, invitations to workgroups/projects, new "likes" to your posts and comments, etc. These notifications are shown at the top right corner:
Notifications that require your action stays active until the end of the user session. To view the notifications history, click the Notifications button.
You can click More notifications to view older notifications.
Temporarily disable notifications
You can select simple mode or advanced mode when configuring notifications. In the simple mode, you can only select channels (Website, mobile and desktop apps; Email; Push) for receiving notifications. In the advanced mode, you can select types of notifications and channels for receiving each type of notifications.