Hi Udesh - Office 365 ProPlus and the Windows LTSC differ fundamentally. Office 365 ProPlus, the cloud-connected version of Office, delivers the most productive and most secure Office experience—with the lowest total cost of ownership for deployment and management. Windows Long-Term Servicing Channel (LTSC), in contrast, provides a supported OS for 10 years intended for specialized devices, such as PCs that control medical equipment, point-of-sale systems, or ATMs. It is challenging for us to provide – and for customers to maintain – an always-up-to-date, cloud-connected application suite on top of an operating system that never changes. Separating Office 365 ProPlus and Windows LTSC allows the two different approaches to address customer needs without compromise. The Office 365 ProPlus clients will still work on LTSC, and will not enter reduced-functionality mode. But Office 365 ProPlus patches or security updates will not be built with LTSC in mind, and may stop being available for Office 365 ProPlus running on un-supported versions of Windows over time. Features or services released after Jan 2020 may not function correctly in this unsupported environment.