Users operating on Windows 10 must enroll in Microsoft's free Extended Security Updates (ESU) program before October 14, 2025, to ensure uninterrupted security updates. Enrollment in the ESU program remains available until it expires on October 14, 2026, but delaying enrollment will result in a gap in security updates. Missing the October 14 deadline does not prevent enrollment in the ESU program, but devices will be more vulnerable during any non-enrollment period. Enrolling in the ESU program does not hinder upgrading to Windows 11 if the PC meets eligibility criteria. Kaspersky experts have raised concerns about privacy implications of requiring a Microsoft account for Windows 11 setup. Nearly 40% of Windows computers still run on Windows 10, with many being fully functional but not compatible with Windows 11. Users have a year to navigate these changes before the next deadline approaches.