, you are essentially driving a car with a 2019 inspection sticker—it might still run, but it’s no longer safe for the road.
Because 5.6.40 is EOL, any vulnerability discovered after Jan 2019 remains unpatched in this version. Notable examples: php version 5640 vulnerabilities link
PHP 5.6.40 in a production environment is a major security risk because it reached its End of Life (EOL) on December 31, 2018 , you are essentially driving a car with
Instead of browsing a static link, use automated vulnerability scanners that return dynamic results. php version 5640 vulnerabilities link
https://www.php.net/manual/en/migration83.php