Windows RT

Windows RT is a mobile operating system developed by Microsoft. It is a version of Windows 8 or Windows 8.1 built for the 32-bit ARM architecture (ARMv7). First unveiled in January 2011 at Consumer Electronics Show, the Windows RT operating system was officially launched 
on August 26, 2012, with the release of three Windows RT-based devices, including Microsoft's original Surface tablet. Unlike Windows 8, Windows RT is only available as preloaded software on devices specifically designed for the operating system by original equipment manufacturers (OEMs). Normal apps such as Google Chrome can't be downloaded on Windows RT through any web browser, the only way to get apps on Windows RT is by using the Windows Store, which is an app store for Microsoft Windows, starting from Windows 8 and Windows 8.1 and is also compatible with some version of Windows Server operating systems, such as Windows Server 2012 and Windows Server 2012 R2.
Support status.
Mainstream support ended on January 9, 2018. In 2021 Microsoft said it’ll stop providing security updates and support for Windows RT after January 10, 2023 (EOL date).