Feature Availability Table

Use a version table during maintenance to distinguish syntax availability from team adoption. A feature can be available in PHP while still being unavailable to an application whose production baseline is older.

Use This Reference When

• Check the production baseline before using new syntax.
• Check CI, static analysis, coding standards, and local tooling.
• Record compatibility constraints in Composer.

Selected Features

| Feature | First available |
| --- | --- |
| Scalar declarations and return types | PHP 7.0 |
| Typed properties | PHP 7.4 |
| Union types and attributes | PHP 8.0 |
| Enums and readonly properties | PHP 8.1 |
| Readonly classes | PHP 8.2 |
| `#[\Override]` | PHP 8.3 |
| Property hooks | PHP 8.4 |
| Pipe operator | PHP 8.5 |

A production upgrade needs more than a table: read every intervening migration guide and execute the application checks.