How The Benefits of Converting From PHP 5 to PHP 7?

How to Upgrade from PHP 5 to PHP 7: Benefits, Features, and Migration Considerations

PHP has changed significantly over the years, and upgrading an older application can bring improvements in performance, language features, security, and maintainability. One important historical upgrade was the move from PHP 5 to PHP 7.

PHP 7 was released in December 2015 and introduced major improvements over PHP 5.6, which had been released in 2014. The PHP 7 series was considerably faster and more memory-efficient than PHP 5, while also introducing new language features and a more modern approach to error handling.

Important today: PHP 7 is now a legacy platform as well. This article discusses the historical benefits of moving from PHP 5 to PHP 7, but a website or application still running an unsupported PHP version should generally be assessed for migration to a currently supported PHP release rather than stopping at PHP 7.

Why Was PHP 7 a Major Upgrade?

PHP 7 was more than a simple version update. It introduced changes to the PHP engine and programming language that could significantly improve the way applications performed and were maintained.

For developers working with older PHP 5 applications, the upgrade could provide several benefits, including better execution speed, lower memory usage, scalar type declarations, return type declarations, improved error handling, anonymous classes, the spaceship operator, grouped namespace imports, and other language improvements.

Key point:

The benefits of PHP 7 were not limited to speed. The newer language features also helped developers write code that was clearer, more predictable, and easier to maintain.

1. Significant Performance Improvements

One of the biggest reasons PHP 7 received attention was its performance. PHP 7 introduced the new Zend Engine 3, often referred to during development as the PHP Next-Generation engine or PHPNG.

Compared with PHP 5.x, PHP 7 could execute many applications considerably faster while using less memory. The exact improvement depended on the application, framework, workload, database usage, configuration, and code quality, so it would be misleading to promise one fixed performance percentage for every website.

For busy websites and applications, improved efficiency could mean that the server was able to handle more requests with the same hardware. In some situations, this could reduce infrastructure pressure and improve the overall responsiveness of an application.

Area	PHP 5	PHP 7
Execution engine	Older Zend Engine	Zend Engine 3
Performance	Lower compared with PHP 7	Substantially improved for many workloads
Memory efficiency	Generally higher memory requirements	Improved memory efficiency

2. Scalar Type Declarations

PHP 7 introduced scalar type declarations for function and method parameters. Developers could specify expected types such as int, float, string, and bool.

This made it possible to communicate more clearly what kind of data a function expected. Depending on how the application was configured and written, type declarations could also help identify incorrect values earlier.

Example: A function that expects an integer can explicitly declare an int parameter rather than relying entirely on documentation or assumptions made by the developer.

Type declarations are particularly useful in larger projects where many developers work on the same codebase. They make function interfaces easier to understand and can reduce some common programming mistakes.

3. Return Type Declarations

PHP 7 also introduced return type declarations. A developer could specify the expected type returned by a function or method.

For example, a function could declare that it returns an integer, string, boolean, or floating-point value. PHP 7 also supported other return types, including class/interface types, arrays, and void in later PHP 7 releases.

Return types improve the readability of code because another developer can understand the intended result of a function without having to inspect its entire implementation.

4. Improved Error Handling

Error handling was another important area changed in PHP 7. Some serious engine errors that previously terminated execution in difficult-to-handle ways could now be represented using Throwable objects and handled through exception-style mechanisms.

PHP 7 introduced the Error class and the common Throwable interface. This created a clearer distinction between traditional exceptions and engine-level errors while providing developers with a consistent way to catch throwable conditions where appropriate.

Why this matters:

Better error handling can make debugging and recovery easier. However, developers should not simply catch every error and ignore it. Proper logging, validation, testing, and meaningful error handling are still essential.

5. Anonymous Classes

PHP 7 introduced support for anonymous classes. An anonymous class is a class without a declared name that can be instantiated directly.

This can be useful when a small class is required only in one particular place. It can also be useful in testing or situations where creating a separately named class would add unnecessary structure.

Anonymous classes should not automatically be considered better than named classes. They are simply another tool available to developers, and the choice should depend on the design and maintainability of the application.

6. The Spaceship Operator

PHP 7 introduced the spaceship operator, written as <=>. Its official name is the combined comparison operator.

It performs a three-way comparison and returns:

• -1 when the left value is less than the right value.
• 0 when the values compare equally.
• 1 when the left value is greater than the right value.

This operator can be particularly convenient when writing comparison logic and custom sorting functions.

The spaceship operator did not make PHP applications automatically faster or safer. Its main advantage was providing a concise and useful language feature for comparison operations.

7. Grouped Use Declarations

PHP 7 introduced grouped use declarations, allowing related classes, functions, or constants from the same namespace to be imported together.

This can make source code shorter and easier to read, particularly in files that use several classes from the same namespace. It is a small feature, but many small improvements like this can make a large codebase more comfortable to maintain.

8. Security and Modern Cryptography

Security was another important reason to move away from unsupported PHP versions. PHP 7 provided a more modern platform than PHP 5 and its ecosystem could support newer security practices and libraries.

However, security should not be described as a single feature that automatically makes every PHP 7 application secure. A secure application also requires updated dependencies, safe authentication practices, secure configuration, input validation, proper access controls, HTTPS, backups, monitoring, and regular security maintenance.

Some PHP 7 releases also added or supported modern cryptographic capabilities. For example, later PHP 7 versions included access to stronger password hashing and cryptographic functionality. Developers should always consider the exact PHP release and available extensions when evaluating security capabilities.

Do not confuse an upgrade with complete security.

Moving from an obsolete PHP version is an important step, but it does not remove vulnerabilities caused by outdated plugins, libraries, application code, weak passwords, incorrect server configuration, or poor security practices.

9. Cleaner and More Maintainable Code

One of the less visible benefits of upgrading PHP is the opportunity to improve the codebase itself. Newer language features can make some older coding patterns simpler and easier to understand.

During a migration, developers can also identify deprecated functions, outdated libraries, incompatible extensions, inefficient code, and security weaknesses. Therefore, a PHP migration can become an opportunity for technical cleanup rather than simply changing the PHP version on the server.

10. Deprecated and Removed Features

PHP 7 removed or changed several features that existed in earlier PHP releases. This was useful for the long-term development of the language, but it also meant that not every PHP 5 application could simply be moved to PHP 7 without testing.

Older applications may depend on deprecated functions, outdated extensions, old frameworks, or coding patterns that are incompatible with PHP 7. This is why migration should be treated as a software upgrade project rather than a simple version-number change.

PHP 5 to PHP 7 Migration: What Should You Check?

Before upgrading an existing application, developers should create a complete picture of the current system. The following checklist can help:

1. Identify the current PHP version and server configuration.
2. Back up the application and database before making changes.
3. Review the source code for deprecated and incompatible features.
4. Check frameworks, CMS platforms, plugins, and libraries for compatibility.
5. Test the application in a staging environment rather than upgrading the live website first.
6. Review database and server dependencies, including PHP extensions.
7. Test forms, login systems, payments, APIs, uploads, email, and administrative functions.
8. Monitor application logs after the upgrade.
9. Plan a rollback strategy in case an unexpected compatibility problem occurs.

Common Mistakes During PHP Migration

• Changing the PHP version directly on a production server without testing.
• Assuming that every PHP 5 application will work unchanged on PHP 7.
• Ignoring outdated plugins, frameworks, or third-party libraries.
• Using old benchmark numbers as a guarantee of real-world performance.
• Assuming that upgrading PHP alone makes an application completely secure.
• Forgetting to maintain a reliable backup and rollback plan.

Should You Still Upgrade from PHP 5 to PHP 7?

From a historical perspective, moving from PHP 5 to PHP 7 was a major improvement. PHP 7 brought better performance, lower memory usage, new language features, improved error handling, and a more modern foundation for PHP development.

However, today the more important question is not whether an application should stop at PHP 7. The PHP 7 branch itself is no longer a current supported platform. Organizations maintaining legacy PHP 5 or PHP 7 applications should therefore evaluate migration toward a currently supported PHP version that is compatible with their application and hosting environment.

The exact target version should be chosen after checking the application's framework, libraries, extensions, hosting environment, and code compatibility. In some cases, a step-by-step upgrade may be safer than attempting a very large version jump in one operation.

A Practical Migration Strategy

Stage	What to Do
1. Audit	Review PHP code, dependencies, extensions, and server configuration.
2. Backup	Create verified backups of files, databases, and important configuration.
3. Test	Create a staging environment and test the application thoroughly.
4. Fix	Resolve deprecated features, compatibility problems, and dependency issues.
5. Upgrade	Move the production environment to the selected supported PHP release.
6. Monitor	Check logs, performance, errors, and important application functions after deployment.

Final Thoughts

The transition from PHP 5 to PHP 7 represented a significant step forward for PHP development. The newer engine delivered major performance and memory-efficiency improvements, while features such as scalar and return type declarations, improved error handling, anonymous classes, the spaceship operator, and grouped use declarations gave developers better tools for building and maintaining applications.

For developers working with legacy software, the most important lesson is that software platforms should not be left unchanged indefinitely. A migration should be planned, tested, backed up, and performed with compatibility and security in mind.

In short: PHP 7 was a major improvement over PHP 5, but PHP 7 itself should now be considered part of PHP's legacy history. If you are maintaining an old PHP application today, focus on a carefully tested migration to a currently supported PHP release rather than treating PHP 7 as the final destination.