Runtime Briefing — PHP 8.1 Release
PHP 8.1 reached GA on 25 November 2021 with enums, readonly properties, and fibers, expanding language safety while triggering application compatibility testing and dependency updates across managed platforms.
Executive briefing: The PHP project published PHP 8.1.0 on , introducing major language features and JIT enhancements that affect frameworks, extensions, and deployment runtimes.
Key runtime updates
- Enums and readonly properties. Native enumerations and
readonlyclass properties alter type modelling, requiring code reviews for backwards compatibility. - Fibers and async support. The new fiber API underpins userland scheduling libraries, reshaping concurrency primitives in frameworks such as Amphp and ReactPHP.
- Performance. JIT improvements and inheritance cache changes modify CPU profiles and may expose latent bugs.
Migration guidance
- Review framework and extension support matrices, especially for Symfony, Laravel, and WordPress components, before promoting PHP 8.1 to production.
- Extend CI pipelines with PHP 8.1 builds, updating Composer constraints and PHPUnit tooling to catch breaking changes.
- Coordinate with hosting providers and container image maintainers to confirm availability of PHP 8.1 packages, security patch cadence, and monitoring integrations.