What are the consequences of maintaining legacy PHP scripts without addressing underlying design flaws?

Maintaining legacy PHP scripts without addressing underlying design flaws can lead to increased technical debt, decreased performance, and difficulty in implementing new features or fixing bugs. To address this issue, it is important to refactor the codebase, identify and fix design flaws, and modernize the codebase to adhere to current best practices.

// Example of refactored code to address design flaws

// Before refactoring
function legacyFunction($input) {
    // legacy code with design flaws
}

// After refactoring
function newFunction($input) {
    // updated code with improved design
}