What to Use as the “sourceAnchor” Attribute in Azure AD Connect

In Azure AD Connect, the sourceAnchor attribute connects an on-premises object to a cloud object. It ensures that a hybrid object has the same identity both on-premises and in Azure. After the sourceAnchor attribute has been set, it is best practice to avoid updating the sourceAnchor attribute value unless it is absolutely necessary to do so. Attributes such as UserPrincipalName or email, for example, should not be used, since they can change if a user’s user name or email changes.