In case of Exchange Server, only emails, calendar, contacts and tasks may be synchronized.
Active Sync also provides for the manual transfer of files to a mobile device, along with limited backup functionality, and the ability to install and uninstall mobile device applications.
On desktops, Active Sync synchronizes emails, calendar, contacts and tasks with Microsoft Outlook, along with Internet bookmarks and files.
Active Sync does not support all features of Outlook.
Outlook 2007 is the only version where i Cloud is affected by the June 13 2017 security update, but attachments are blocked in some scenarios in Outlook 2010, 2013, 2016.
Exchange, Gmail, and users don't need to use i Cloud for their calendar and contacts.
These accounts support syncing to the device and all data is already in the "cloud" and syncs to all devices and computers.
If Outlook keeps disabling the i Cloud add-in, see i Cloud Doesn't Sync We're seeing a lot of questions (and complaints) about Apple's i Cloud service and it's integration with Microsoft Outlook.
i Cloud is supported in current versions of Outlook and with Office 365 subscriptions.