End of life (EOL) is the date after which a vendor stops releasing updates and security patches for a piece of software or hardware. The product keeps working, but newly discovered flaws are no longer fixed. Windows 10, for example, reached end of support on October 14, 2025, except for organizations enrolled in Extended Security Updates (ESU).
Go deeper on the TecnetBlog: Security Risks of EOL Software and Hardware
end of support, EOS, EOL software, legacy systems, unsupported software