Clean install of v188.8.131.5273& restart on two different computers (Windows), one with Office 2010 and one with Office 2013.
The feature is still listed:
Microsoft Outlook Contacts - make calls, send faxes, send texts from within
Microsoft Office - send faxes from within Office applications (Windows)
RingCentral for Desktop seamlessly integrates with Microsoft Office and Outlook applications, so you can call, text, or fax your contacts from within Office.**