Windows 10 Enterprise LTSC 2021 reaches mainstream end-of-support on January 13, 2027, giving enterprises roughly five months of free security patches before transitioning to paid extended support. Unlike consumer editions that ended support in October 2025, the LTSC variant follows Microsoft's Fixed Lifecycle Policy, offering extended protection until approximately January 2032 at a cost starting at $61 per device in year one, which doubles annually. The biggest hurdle for many organizations is that legacy special-purpose devices like ATMs, medical systems, and industrial controllers often lack the TPM 2.0 and processor requirements needed to upgrade to the recommended successor, Windows 11 IoT Enterprise LTSC. IT leaders should immediately inventory their LTSC deployments to decide whether devices can be migrated to supported hardware or if they must commit to extended security updates to maintain compliance through 2032.

Windows 10 LTSC 2021 Hits Mainstream EOL in Five Months: What IT Leaders Need to Know

Extended support costs are climbing fast, and legacy hardware might force some organizations into unplanned replacements.

Windows 10 Enterprise LTSC 2021 will lose mainstream support on January 13, 2027. That leaves roughly five months to sort out the patching and replacement strategy. Consumer Windows 10 Home and Pro editions already dropped off the cliff back in October 2025. LTSC operates under Microsoft's Fixed Lifecycle Policy, which means it gets a significantly longer runway. You have until approximately January 2032 for extended support before the whole thing goes dark.

The Post-EOL Math: ESU Costs and Hardware Headaches

The financial side of things is where the real pain starts. Microsoft's commercial Extended Security Update program runs $61 per device for the first year. If you need cloud management through Windows Autopatch or Intune, you can knock that down to roughly $45. However, at the same time, the price doubles every single year after that. Not cheap. Over a three-year window, you're looking at up to $427 per device if you enter the program mid-stream. And that's not even accounting for the hardware upgrades that might be necessary.

Keep in mind that LTSC is built for special-purpose devices. MRI machines, POS terminals, industrial control systems, and ATMs. These are exactly the kinds of machines that often run on legacy silicon. Windows 11 IoT Enterprise LTSC, Microsoft's recommended successor, demands TPM 2.0, Secure Boot, and an 8th Gen Intel processor or newer. Many of the systems currently running LTSC 2021 simply won't pass that hardware handshake.

If you're keeping score, you have three realistic options. First, you can stay on Windows 10 LTSC 2021 through extended support until roughly 2032. Second, you can bite the bullet and purchase the ESU licenses to keep getting security patches. Third, you replace the hardware entirely with devices that meet the Windows 11 requirements.

For now, Microsoft continues to ship monthly cumulative security updates. The latest patch, KB5099539, dropped on July 14, 2026, bringing the LTSC build to 19044.7548. That keeps the system patched through the mainstream EOL date. After January 13, 2027, you'll need to activate a commercial 5-by-5 key or rely on your Intune configuration to keep the security updates flowing.

Head here to review the full lifecycle dates and pricing details from Microsoft's official documentation.