Reader now marks an entry read when you open it, move to it with the keyboard, or open its original page. Unread totals update immediately, and Mark unread reverses the change.
A selected subscription is named above the timeline, Mark read actions stay within that subscription, and older entries are available through page controls. Subscriptions are checked in the background, failed checks are shown beside the affected subscription, and publisher-hosted images load only when you ask for them.