Microsoft previously offered two synchronization tools for hybrid identity implementation: Windows Azure Active Directory Sync (DirSync) for single forest Active Directories and Microsoft Azure Active Directory Sync (Azure AD Sync) for multi-forest and other advanced scenarios.
Both of these tools have been replaced by Azure AD Connect for all scenarios and even more capabilities in the past. DirSync and Azure AD Sync are no longer being updated and will no longer be supported after 13th of April 2017. So make sure you move to Azure AD Connect before deadline date so your identity replication is not impacted.
Microsoft provides further information on how to transition to Azure AD Connect on the Upgrade Windows Azure Active Directory Sync and Azure Active Directory Sync documentation page.
That’s all for now.
Stay tuned and best regards,