What potential pitfalls should be considered when updating older PHP scripts?

When updating older PHP scripts, potential pitfalls to consider include deprecated functions or features that may no longer be supported in newer PHP versions, changes in syntax or behavior that could break existing functionality, and security vulnerabilities that may have been addressed in newer versions. It is important to thoroughly test the updated script in a development environment before deploying it to ensure that it functions as intended. 

// Example of updating an older PHP script to use mysqli instead of deprecated mysql functions

// Old code using mysql functions
$conn = mysql_connect('localhost', 'username', 'password');
mysql_select_db('database', $conn);
$result = mysql_query('SELECT * FROM table', $conn);
while ($row = mysql_fetch_assoc($result)) {
    // Process data
}
mysql_close($conn);

// Updated code using mysqli functions
$conn = mysqli_connect('localhost', 'username', 'password', 'database');
$result = mysqli_query($conn, 'SELECT * FROM table');
while ($row = mysqli_fetch_assoc($result)) {
    // Process data
}
mysqli_close($conn);

Keywords

Outdated PHP versions Deprecated functions Incompatibility issues Security vulnerabilities Code refactoring

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