Kanboard supports RSS feeds for projects and users.
- Project feeds contains only the activity the project
- User feeds contains the activity stream of all projects the user is member
Those subscriptions are only activated when the public access is enabled in the user profile or in the project settings.
Go to Project settings > Public access.
Go to User profile > Public access.
The RSS link is protected by a random token, only people who knows the url can access to the feed.