The current state.
WHAT HAS CHANGED
Substantially improved performance
Modern language features: types, attributes, enumerations
Mature frameworks and tooling A strong package ecosystem
WHY IT REMAINS WIDELY USED
It runs on essentially all shared hosting An enormous body of existing applications Deployment is straightforward Hosting is cheap and available everywhere
WHY THAT MATTERS HERE
Shared hosting is the accessible option, and it runs PHP without configuration.
WHAT THE EXECUTION MODEL IS
A process per request, starting fresh each time.
WHAT THAT MEANS
No state persists between requests, which simplifies reasoning and prevents a class of bug.
WHAT IT COSTS
Startup work on every request, addressed by caching and by persistent runtimes.
WHAT TO USE
A current supported version.
WHY
Older versions receive no security fixes, and the differences are substantial.
WHAT TO VERIFY
That the version serving pages matches the version on the command line.
WHY
They frequently differ, which causes confusing failures.
