Windows Server 2012 R2 was released on October 18, 2013. It was unveiled on June 3, 2013 at TechEd North America. According to Windows Server 2012 R2 datasheet published on May 31, 2013, there are four editions of this operating system: Foundation, Essentials, Standard and Datacenter.
As with Windows Server 2012, the Datacenter and Standard editions are feature identical, varying only based on licensing (particularly licensing of virtual instances). The Essentials edition has the same features as the Datacenter and Standard products, with some restrictions.
A further update, formally designated Windows Server 2012 R2 Update, was released in April 2014, a cumulative set of security updates, critical updates and updates.