Microsoft is shortening the support lifecycle of Windows 10 Enterprise Long Term Servicing Channel (LTSC) releases from 10 years down to only five years. Microsoft advises users who want to keep their devices on the same Windows version for years (more than five) to switch to Windows 10 IoT Enterprise LTSC releases. The company is cutting down the available time to avoid installing Windows 10 feature updates in half for users of devices running LTSCs. The changes will be enacted starting with the second half of this year, when the next version of 21H2 are scheduled to be launched.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-cuts-down-windows-10-enterprise-ltsc-support-to-5-years/