PhpStorm修改语言等级：PHP Language Level is synchronized with composer.json-CFANZ编程社区

修改路径

Preferences > Languages & Frameworks > PHP > php language level

PhpStorm修改语言等级：PHP Language Level is synchronized with composer.json_php

如果发现是 php 5.4，无法修改，可以先设置 composer

Preferences > Languages & Frameworks > PHP > Composer

取消勾选 Synchronize IDE Settings with composer.json

PhpStorm修改语言等级：PHP Language Level is synchronized with composer.json_php_02

参考
Phpstorm 更改php language level