Keeper.sh now connects to calendar servers that require digest authentication, a sign-in scheme used by many self-hosted and university CalDAV servers. Before this release, those servers rejected credentials that were correct, because Keeper.sh only used the more common scheme.
Both schemes now work. When a server asks for digest, Keeper.sh completes the exchange with the details you already entered. Nothing about how you enter them changes, and there is no setting to find.
Keeper.sh records which scheme your server wants the first time it says so, and later syncs answer correctly on the first attempt. If a server refused your details at the connect screen before, try connecting again.
What each calendar service asks for lists the details a CalDAV server needs.