Windows Server 2012 R2

Windows Server 2012 R2, codenamed "Windows Server Blue", is the eleventh version of the Windows Server operating system by Microsoft, as part of the Windows NT family of operating systems. It was unveiled on June 3, 2013, at TechEd North America, and released on October 18 of the same year. It is the successor to Windows Server 2012, and is based on the Windows 8.1 codebase. Windows Server 2012 R2 is the final version of Windows Server to use the "R2" suffix, which had been used since the release of Windows Server 2003 R2 in 2005.

Windows Server 2012 R2 removed support for processors without CMPXCHG16b, PrefetchW, LAHF and SAHF. A further update, formally designated Windows Server 2012 R2 Update, was released in April 2014. It is a cumulative set of security, critical and other updates. Windows Server 2012 R2, like previous versions of Windows Server before it and versions after it, is only compatible with 64-bit processors. Windows Server 2012 R2 was succeeded by Windows Server 2016, which is derived from the Windows 10 codebase. Mainstream support for Windows Server 2012 R2 ended on October 9, 2018, and extended support ended on October 10, 2023. Windows Server 2012 R2 is eligible for the paid Extended Security Updates (ESU) program, which offers continued security updates until October 13, 2026.

Features
The following features are introduced in Windows Server 2012 R2:
 * 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
 * Integrated Office 365 support (Essentials edition)
 * User interface changes reflecting Windows 8.1, including visible Start button.
 * UEFI-based virtual machines
 * Upgrades from driver emulators to synthetic hardware drivers to minimize legacy support
 * Faster VM deployment (approximately half the time)
 * Internet Information Services 8.5: Support for logging to Event Tracing for Windows and the ability to log any request/response headers. To improve scalability, if IIS is configured with 100 or more web sites, by default it will not automatically start any of them. Alongside this, a new "Idle Worker Process Page-Out" configuration option has been added to application pools to instruct Windows to page-out the process if it has been idle for the idle time-out period (by default, 20 minutes).
 * Server Message Block: Performance and event logging quality improvements, support for Hyper-V Live Migration over SMB, bandwidth prioritization management, and the ability to remove SMB 1.0 support
 * Windows Deployment Services: Support for managing WDS via PowerShell.
 * Windows Defender is available in a Server Core installation, and is installed and enabled by default.
 * IP Address Management (IPAM): Extended to support role-based access control, allowing for fine-grained control over which users can view or change configurations for DHCP reservations, scopes, IP address blocks, DNS resource records, etc. Additionally, IPAM can integrate with System Center Virtual Machine Manager 2012 R2 to have coordinated IP policy across both physical and virtual environments. The IPAM database can be stored in a SQL Server instance instead of Windows Internal Database.
 * Group Policy has a new "Policy Cache" setting which allows domain-joined machines to store a copy of the group policy settings on the client machine and, depending on the speed of access to the domain controller, use those at startup time instead of waiting for the policy settings to download. This can improve startup times on machines that are disconnected from the company network. New Group Policy settings have been added to cover new features in Windows 8.1 and Internet Explorer 11, such as enabling/disabling SPDY/3 support, configuring start screen layouts, and detecting phone numbers in web pages.
 * TLS support is extended to support, "Transport Layer Security (TLS) Session Resumption without Server-Side State", which improves performance of long-running TLS-secured connections that need to reconnect due to session expiration.
 * Hyper-V role and Hyper-V management console are added to the Essentials edition.
 * Windows Server Update Services was made available for Windows Server 2012 R2 Essentials edition.
 * ReFS gained support for alternate data streams and automatic error-correction on parity spaces.

Editions
According to the 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.

Support lifecycle
Microsoft originally planned to end mainstream support for Windows Server 2012 and Windows Server 2012 R2 on January 9, 2018, with extended support ending on January 10, 2023. In order to provide customers the standard transition lifecycle timeline, Microsoft extended Windows Server 2012 and 2012 R2 support in March 2017 by 9 months. Windows Server 2012 reached the end of mainstream support on October 9, 2018 and entered the extended support phase, which ended on October 10, 2023.

Microsoft announced in July 2021 that they will distribute paid Extended Security Updates for volume licensed editions of Windows Server 2012 and Windows Server 2012 R2 for up to 3 years after the end of extended support. For Windows Server 2012 and Windows Server 2012 R2, these updates will last until October 13, 2026. This will mark the final end of all security updates for the Windows NT 6.2 product line after 14 years, 2 months and 12 days and will also mark the final end of all security updates for the Windows NT 6.3 product line after 13 years, 1 month and 16 days.