Hi Gary,
The support matrix is here:
community.sagecrm.com/.../25765.aspx
Short answer: it should work, depending on your CRM and client OS version. The Exchange Lite plugin works with 64-bit copies of Outlook, whereas the classic plugin is 32-bit only.
Pro Plus (the version of Outlook you get by default with Office 365) has been tested, and it works. Most of the issues we've been seeing aren't to do with installation as such, but are actually the plugin being automatically disabled in Outlook.
Most of the time, this is caused by an issue with Microsoft's Visual Studio Tools for Office (VSTO). This suppresses error messages by default. You can enable them by adding two environment variables on the client, called VSTO_SUPPRESSDISPLAYALERTS and VSTO_LOGALERTS, with values of 0 and 1 respectively. Generally this is fixed by downloading and installing the latest VSTO version from Microsoft.
If this doesn't fix the issue, and you need to log a case with your local support team, then they'll need your CRM version, client OS version and exact version of Outlook.
Thanks,
Rob
*Community Hub is the new name for Sage City