Migrating From PHP 7.0 to PHP 8.1: All You Need To Know!

PHP (Hypertext Preprocessor) is one of the most sought-after server-side scripting languages. Its open-sourced nature, easy learning curve, and the ability of the PHP code to get effortlessly embedded into HTML have made it a popular name in web development. It can also be combined with JavaScript and CSS. Also, a major portion of WordPress software is powered by PHP, which makes it indispensable for WordPress users. 

Other popular CMSs like Joomla, Drupal, and Magneto also depend on PHP. PHP runs on all major operating systems, including Windows, macOS, and Linux; syncs with most databases, including MySQL, MongoDB, and Postgres; and is supported by a majority of the web servers like Apache, IIS, etc. Several biggies, including Facebook, Shopify, and Wikipedia, have leveraged PHP to create powerful and interactive websites.

 The PHP team has been quite proactive in rolling out updated versions based on ongoing trends and technological advancements. The latest updated version is PHP 8.1, which promises ease of usage and several other advantages. Have you updated to the latest PHP version? If you’re still using the older versions, it’s time to consider updating to PHP 8.1, as it brings a lot to the table, including improvements in performance, syntax, and security. 

 This post provides insights on the offerings of the latest PHP version and guides you through the process of how to migrate PHP from 7.0 to 8.1. Let’s commence!

Reasons Why You Need To Upgrade to PHP 8.1

Here’s why it would be a smart move to update your existing PHP version to the latest one!

PHP 8.1 introduces a wide range of add-ons, including new interfaces, classes, and functions. The new additions will enhance performance, speed up the code, and safeguard your code against security-related vulnerabilities. Thanks to the new language functionalities, you’ll be able to create a code that’s more expressive and maintainable.  

The PHP versions until 7.4 are outdated now and are not actively supported any longer. On the other hand, PHP 8.1 will receive active support till November 25, 2024, and the team has announced more security updates coming up for this version. Hence, websites or web apps still using older versions are missing out on several avant-garde functionalities and lagging behind with regard to performance. Moreover, any security issues cropping up in the older versions are likely to remain unpatched due to the absence of active support. As such, your website or web app is exposed to security risks like DoS, XSS, code execution, directory traversal, corruption of memory, etc.

When you execute the PHP code on the server, the results get displayed on the client’s web browser. PHP can also be used along with technologies like JavaScript, HTML, and CSS.

Major Updates in PHP 8.1

Support for Enums (Enumerations)

Enums (Enumerations) refers to a kind of data type defined by the user containing a set of possible values. Enums are used for holding a value for every case, optionally declaring “int” or “string” as backed values, extending classes, and implementing interfaces.

Fibers

These are primitives that enable you to build code blocks that you can pause and resume, similar to generators. You can pick these blocks up from any place within the stack. Primitives can be used to implement lightweight cooperative concurrency. With Fibers, you can eliminate the boilerplate code that was earlier viewed with Generator-based coroutines or Promise::then().

Nullsafe Operator

With this operator, one can chain the method calls without having to worry about null references. When a method is called on an object that may or may not be null, the nullsafe operator’s job is to make sure that the method gets called only when the object isn’t null. 

Match Expression

Using this feature, values can be matched in a more brief and flexible manner. You specify several cases along with their associated values. Then, the relevant case can be selected based on an expression’s value using the keyword “match.” 

Performance Enhancements

Version 8.1 comes with several performance enhancements like JIT improvements and fixes. Improvements in memory usage and SPL file-system operators have been made. Capabilities like serializing or unserializing optimizations have been added. With V8.1, one can avoid hash lookup, lowercasing, & the relinking of classes for every request. 

Added Supports

Support has been added for categories like attributes, named arguments, etc. The existing support for Unicode has been improved upon. Earlier, array unpacking support was available for numeric keys only; now, it’s available for string keys as well. 

Things To Do in PHP Code After Server Upgrade/Change/Rename

1. Include the new server name/ip in the code if conditions are used based on the server name/ip.
2. Create all necessary folders on the new server, or else PHP could throw errors in fopen(), fwrite() etc., file operations.
3. Copy the necessary data from the old server to the new server. (For example, images, logo, cron, data stored on cloud storage, etc.).
4. Sometimes we could get memory issues like --> PHP message: PHP Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 20480 bytes). These are the approaches to be adopted to fix this issue:

1. Fetch only the necessary columns in SQL query and avoid joins
2. Limit the usage of loops in the code.
3. Load limited data or implement lazy loading. (If a large number of records are to be fetched)

What Are the Common PHP Errors Likely To Occur After Upgrading PHP From 7.0 to 8.1, and How Can These Issues Be Resolved?

1. Methods with the same name as the classes are no longer interpreted as constructors. The __construct() method should be used instead.
PHP 8.1 fix: Check all the constructors defined in the class files and use __construct() instead of the class name. 

2.  To reference array, [] operator is not allowed.

PHP 7.0: $cities[] = $city; (Variable declaration change example in PHP 8.1)

PHP 8.1 fix: array_push($cities,$city);

An error occurred in 8.1: [] operator not supported. 

3. Error shared in pt.1 can lead to json_decode() error as it takes $cities as strings and not an array if the fix is not made according to PHP 8.1.

PHP 7.0: @json_decode($cities); (function call change example in PHP 8.1)

PHP 8.1 fix: @json_decode(json_encode($cities));

An error occurred in 8.1: json_decode(): Argument #1 ($json) must be of type string, and an array is given.
4. get_magic_quotes_gpc() method is deprecated since PHP 7.4

An error occurred in 8.1: Uncaught Error: Call to undefined function get_magic_quotes_gpc();

5. Deprecated variable and parameter declaration.
 PHP 8.1 fix: The function call should match the function definition and its parameter sequence.  In the function definition, default parameters should be assigned from right to left.
Eg: function test_function(int $var1 , int $var2='101', int $var3='abc')

6. Error mentioned in the pt.2 PHP 7.0 version can lead to multiple errors in array functions. A few such array functions are listed below:

I)implode() : Error occurred in 8.1 : TypeError: implode(): Argument #2 ($array) must be of type array
II)count() : Error occurred in 8.1 : TypeError: count(): Argument #1 ($value) must be of type Countable|array
III)in_array() : Error occurred in 8.1 : TypeError: in_array(): Argument #2 ($haystack) must be of type array
IV)array_keys() : An error occurred in 8.1 : TypeError: array_keys(): Argument #1 ($array) must be of type array.

I hope this PHP migration guide will help you to reap the benefits of the newest functionalities and enhancements. PHP 8.1 is secure and reliable and comes with disruptive offerings that optimize your PHP website’s performance and safety. It’s advisable to upgrade to PHP 8.1 as it makes the web development process easier and more effective, allows you to handle errors in a better way, and simplifies maintenance post-deployment. It’s important to note that while migrating to the new PHP version, you need to test your code thoroughly before deploying in production; otherwise, compatibility issues might crop up.