How can outdated references or documentation impact the effectiveness of PHP code, as seen in the forum thread discussion?

Outdated references or documentation can lead to using deprecated functions or incorrect syntax in PHP code, which can result in errors or vulnerabilities. To solve this issue, it is crucial to stay updated with the latest PHP documentation and best practices.

// Example of using an outdated function that may cause issues
$timestamp = mktime(0, 0, 0, 13, 32, 2021);

// Updated code using the correct function
$timestamp = mktime(0, 0, 0, 12, 25, 2021);