Windows 11 is a major release of the Windows NT operating system developed by Microsoft that was released in October 2021. Starting with Windows 10, Microsoft described Windows as an "operating system as a service" that would receive ongoing updates to its features and functionality, augmented with the ability for enterprise environments to receive non-critical updates at a slower pace or use long-term support milestones that will only receive critical updates, such as security patches, over their five-year lifespan of mainstream support.