Essentials was the cheapest at $425 ... 8.1 a year after the launch of Windows 8, it also launched Windows Server 2012 R2 in the same time frame. It went gold on August 27, 2013, and officially ...
R2 also added storage tiering (see HSM) and Workplace Join, the latter enabling user's laptops and mobile devices to function in an Active Directory domain. See Windows Server Essentials.