When an original event changes, Keeper.sh now updates its copy on an iCloud, Fastmail or other CalDAV calendar in place. Before this release, it deleted the old copy and created a new one.
Deleting and recreating was most visible on shared calendars, where one change could notify everyone sharing the calendar twice. An update in place is a single change, so people see the event change instead of disappearing and coming back.
Google Calendar and Outlook destinations work as before. If a CalDAV server rejects an update, Keeper.sh falls back to replacing the copy, so the destination still ends up matching the original.
How a copy follows the original explains how Keeper.sh keeps copies in step.