PHP is the backbone of countless web applications, powering nearly 80% of websites globally. However, sticking to outdated versions such as PHP 7—or even unsupported PHP 8 releases—introduces significant risks and missed opportunities for developers and businesses alike.
With PHP 8.5 now available, there's never been a better time to modernize your applications. If you're still running an older version of PHP, it's time to ask: why should you upgrade to PHP 8.5 (or at least a supported PHP version)?
Editor's note (2026): This article was originally published when PHP 8.4 was the latest stable release. It has been updated to reflect PHP 8.5 while preserving the original discussion about why keeping PHP current matters.
Why you should stay on a supported PHP version
Unmatched performance boost
PHP 8, starting with PHP 8.0 and its Just-In-Time (JIT) compiler, introduced remarkable performance improvements over PHP 7. Each subsequent release (including PHP 8.5) continues to refine the engine with incremental performance optimizations, reduced memory usage, and a better developer experience. Upgrading translates into better scalability, improved responsiveness, and lower infrastructure costs.
Improved security
PHP 7.x is no longer supported, and older PHP 8 releases will eventually reach their end of life as well. Running unsupported versions exposes your applications to known vulnerabilities that can compromise user data and system integrity.
Choosing a supported PHP version ensures your applications continue receiving security updates and bug fixes.
You can check the official End of Life page: https://www.php.net/eol.php
Supported PHP versions are listed here: https://www.php.net/supported-versions
Developer productivity
Every PHP release introduces features that simplify development and improve code quality. PHP 8 brought major innovations such as named arguments, union types, match expressions, enums, readonly properties, property hooks, and asymmetric visibility. PHP 8.5 continues this evolution with additional language improvements and developer-friendly APIs.
Upgrading means writing cleaner, safer, and more maintainable code.
Future-proofing your application
Running a supported PHP version keeps your applications compatible with the latest frameworks, libraries, and hosting platforms, many of which increasingly target PHP 8.5 or recent supported PHP releases.
Staying current also makes future upgrades much easier. Instead of facing large migration projects every few years, you can adopt new releases incrementally with minimal effort.
Why the community benefits from collective upgrading
When developers collectively embrace PHP 8.5 and, more importantly, stay current with each PHP release, the entire ecosystem benefits. Fewer outdated installations mean fewer insecure systems exposed on the Internet. Hosting providers can focus on modern environments, framework maintainers can innovate faster, and the PHP core team can spend more time building new features instead of maintaining legacy versions.
Keeping PHP up to date is a collective investment in a healthier ecosystem.
How to upgrade to PHP 8.5
Upgrading might sound daunting, especially if you manage a large legacy codebase, but modern tools and best practices make the process much easier than it used to be.
Assess compatibility and automate code upgrades with Rector
Start by analyzing your application to identify compatibility issues. Tools like Rector (using dry-run mode) can scan your codebase, detect deprecated features, and automatically modernize your code.
Rector is a powerful refactoring tool that helps migrate applications to newer PHP versions by automatically updating syntax, replacing deprecated APIs, and applying modern coding standards.
For example, if you want Rector to upgrade your codebase to the latest PHP features, configure:
LevelSetList::UP_TO_PHP_85
Rector will automatically apply transformations introduced in PHP 8.5 while also incorporating improvements from previous releases, such as property hooks, asymmetric visibility, the #[Deprecated] attribute, and many other language enhancements.
To learn more about Rector, check out my article: Starting with Rector PHP: Improving Your PHP Code with Automation.
Test thoroughly
A PHP upgrade is still a significant platform change, so testing remains essential. Set up a staging environment running PHP 8.5, execute your unit and integration tests, and perform end-to-end testing before deploying to production.
Continuous Integration (CI) pipelines make this process significantly safer.
Gradual rollout
For large applications or distributed infrastructures, consider deploying PHP 8.5 incrementally. Upgrade development and staging environments first, then gradually roll out production servers while monitoring performance and application health.
Key features introduced throughout PHP 8.x
Here are some of the most significant improvements introduced throughout the PHP 8.x series.
Performance and optimization
- Just-In-Time (JIT) compiler (PHP 8.0)
- Continuous engine optimizations across PHP 8.x
- Memory optimizations and JIT improvements (PHP 8.4)
- Runtime refinements and performance improvements (PHP 8.5)
Enhanced development experience
- Union types (PHP 8.0)
- Named arguments (PHP 8.0)
- Enums (PHP 8.1)
- Readonly properties and readonly classes (PHP 8.1, 8.2)
- Standalone types (
true,false,null) (PHP 8.4) - Property hooks (PHP 8.4)
- Asymmetric visibility (PHP 8.4)
- Pipe operator (
|>) for readable data-processing pipelines (PHP 8.5) - Clone-with syntax for immutable object patterns (PHP 8.5)
Improved code readability
- Match expressions (PHP 8.0)
- Attributes (PHP 8.0)
-
#[Deprecated]attribute (PHP 8.4) -
#[NoDiscard]attribute to warn when important return values are ignored (PHP 8.5) - Object API for BCMath (PHP 8.4)
- Instantiating objects without unnecessary parentheses (PHP 8.4)
Security and reliability
- Deprecated dynamic properties (PHP 8.2)
- JSON validation improvements (PHP 8.3)
- Continuous type-system improvements throughout PHP 8.x
- Built-in URI extension with RFC 3986 and WHATWG-compliant URL parsing (PHP 8.5)
Developer-friendly utilities
- Array unpacking with string keys (PHP 8.1)
- New functions such as
mb_str_pad()andfsync()(PHP 8.3) - HTML5 support in ext-dom (PHP 8.4)
- New array helper functions (PHP 8.4)
-
array_first()andarray_last()helper functions (PHP 8.5) - Improved fatal error backtraces for easier debugging (PHP 8.5)
Conclusion
Upgrading to PHP 8.5 (or at least staying on a supported PHP version) is not just about shiny new language features. It's about securing your applications, improving performance, reducing technical debt, and ensuring long-term compatibility with the modern PHP ecosystem.
Modern tools such as Rector make migrations significantly easier than they were a few years ago, allowing teams to upgrade incrementally instead of facing massive migration efforts.
Don't wait until your PHP version reaches end of life—upgrade today and help build a stronger, faster, and safer PHP ecosystem.
Top comments (4)
Great post as always 👏
I miss the PHP 6 days :(
The (or at least PHP 8.x) part of the title got me by surprise. I been using php 8 so long I'm getting nostalgic about the version 5 and 7 days.
But I did a search and from the data I found a lot of people and websites still use version 7. The only reason I can think of is Wordpress. The requirements still support 7.4. But that version is dead for 2 years. Even the early 8.x versions are already dead or on security support.
I understand there are people who think the development cycles are too short. Nobody wants to keep updating their code when there is no benefit. You don't rebuild your house because a new kind of brick is produced.
With all the new features in php 8 like much better type hinting, enums, attributes instead of comments, making the language behave more like a compiled language instead of a script language, making it multithreading with fibers, and so much more. I can't believe more people and sites are already using a supported php 8 version.
Thank you for your feedback @xwero . Initially, the title was "Why You Should Upgrade to PHP 8.4." However, I felt that was too strong of a statement, so I adjusted it to include "(or at least PHP 8.x)." That said, you're right—encouraging upgrades to 8.0 or 8.1, which are no longer maintained, doesn't make much sense. If someone is upgrading from PHP 7 or 5 to version 8, they should at least move to a fully supported minor version. I think I’ll revise the title to focus on "at least PHP 8.3" instead of 8.x.
If I can make a suggestion: Upgrade to a supported php 8 version, and why 8.4 is the best now.
Or something in that line :)