How to read PHP version statistics

The collected series describe different populations and must remain separate:

• Composer: package installation observations by PHP version, including repeated downloads and CI activity. This is not a census of people or production servers.
• WordPress: the versions reported by the WordPress population. This is a different installation base, not a denominator that can be averaged with Composer.

The Packagist chart page exposes historical series inside its HTML. The collector parses that data without executing JavaScript and stores the monthly series in dated observations. The WordPress API provides a current percentage snapshot; history in this repository starts with its first observation. Current days/months may be incomplete.

A share changing over time does not prove that the same projects migrated. Similarly, a package's minimum PHP constraint states compatibility policy, not observed runtime usage.

Related: package evidence, support windows.