Complex sentence: If a product is Common Criteria certified, it doesn't necessarily mean it is completely secure, for example Microsoft Windows 2000 is a certified product of EAL4 +, but regular security patches for security vulnerabilities are still published by Microsoft for Windows 2000.
Split into simpler sentences: If a product is Common Criteria certified, it does not necessarily mean it is completely secure. For example Microsoft Windows 2000 is a certified product of EAL4 +, but regular security patches for security vulnerabilities are still published by Microsoft for Windows 2000.