Windows Server 2012 R2 is the latest version of Windows Server , currently in preview stage. It was unveiled on 2013-06-03 at TechEd North America , with a preview release on 2013-06-24. A download version on 2013-06-25 was made available.
This is the Server Counterpart of Windows 8.1. it replaces Windows Server 2012 and was replaced by Windows Server 2016.
Hardware Compatibility
Windows Server 2012 R2 is officially compatible with Intel processors up to Skylake (6th Generation). On Kaby Lake (7th Generation) up to Coffee Lake (8th/9th Generation), Server 2012 R2 is not supported due to a lack of Windows Update and Intel Graphics, however, hacks have been made to get both working. For Ice Lake (10th Generation) up to Alder Lake (12th Generation), no known hacks have appeared for Intel Graphics, but the chipset drivers for Ice Lake, Tiger Lake (11th Generation), and Alder Lake have been confirmed to install without any issues.
Editions
According to Windows Server 2012 R2 datasheet published on 2013-05-31, there will be three editions of this operating system: 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 Hyper-V VMs). The Essentials edition has the same features as the Datacenter and Standard products, with some restrictions.
Changes
As of preview version ,
Automated Tiering: Storage Spaces stores most frequently accessed files on fastest physical media
Deduplication for VHD: Reduces the storage space for VHD files with largely similar contents by storing the similar contents only once.
Windows PowerShell v4, which now includes a Desired State Configuration (DSC) feature.
Web Application Reverse Proxy.
Integrated Office365 support.
The return of the Windows Start Button.
Builds
Milestone 1
Milestone Preview
9400.fbl_sfs_dev1_pr.130506-2030 9402.winmain.130507-1720 9410.fbl_partner_out21.130518-1332 
9431.winmain_bluemp.130615-1214 RTM
9600.16384.winblue_rtm.130821-1623 Spring 2014 Update pre-release
9600.16610.winblue_s14.140201-1007 9600.17019.winblue_gdr.140205-2003 9600.17025.winblue_gdr.140214-1706 Spring 2014 Update
9600.17041.winblue_gdr.140305-1710 9600.17415.winblue_r4.141028-1500 
