Azure AD Connect: High Availability with Staging Mode
The ability to run an Azure AD Connect installation in staging mode, prepared identically by importing the active configuration, allows a High Availability solution to be created for Azure AD synchronization with minimal effort. In case of a disaster recovery of the Azure AD Connect service, only the staging mode on the prepared server can be deactivated due to the high availability. The synchronization from Active Directory to Azure Active Directory continues to work seamlessly.
Azure AD Connect: Migration from Passthrough Authentication (PTA) to Password Hash Synchronization (PHS)
Migrating from Passthrough Authentication to Password Hash Sync (PHS) synchronizes passwords from the on-premises Active Directory instance to Azure AD. This is a considerable gain in convenience for users. From now on, they can sign in with the same credentials (user name, password and optionally with multi-factor authentication).This increases productivity and at the same time reduces user support costs.