PHP 8.1
PHP 8.1 is a release of the PHP language shipped in November 2021 that enriched the language with mechanisms previously known mainly from strongly typed languages. Its most important addition was native enumerations, or enums, along with fibers, which provide the foundation for asynchronous processing.
Why PHP 8.1 mattered
PHP 8.1 focused on language maturity and better data modelling:
- enums (enumerations) — a safe way to define closed sets of values, such as statuses or roles;
- readonly properties — object fields that cannot be changed after initialisation, supporting data immutability;
- fibers — a low-level mechanism for pausing and resuming execution, the basis for asynchronous libraries;
- readonly arrays in arguments and the new first-class callable syntax — clearer passing of functions as values.
Enums quickly became one of the most eagerly adopted features of modern PHP, because they removed the need to define sets of constants and improved type safety.
Practical applications
PHP 8.1 was widely adopted across the ecosystem — modern frameworks, including Laravel, began making heavy use of enums and readonly properties. Thanks to its rich feature set and long window of security support, this version became a popular production base for new projects. Applications are best run on a currently supported 8-series release, and modern hosting and VPS servers let you choose the right PHP version and safely test your code on it before deployment.
Enums as a change to everyday work
Of all the PHP 8.1 additions, enums changed everyday coding the most. Previously, developers modelled closed sets of values, such as order statuses or user roles, using loose constants or strings, which easily led to typos and hard-to-spot bugs. Native enumerations enclosed those values in a safe, typed mechanism that works with editor autocompletion and static analysis, markedly reducing the number of mistakes.