Yii2 2.0.49 reports an error in PHP 7.4

[xiays]

Description

ccording to the official Yii2 documentation, the latest version supporting PHP 7.4 is Yii2 2.0.49. However, after installing it following the official guidelines, we found that the application fails to run properly.
Installation command:
composer create-project --prefer-dist yiisoft/yii2-app-basic basic 2.0.49
After installation, we confirmed that the Yii2 version is indeed 2.0.49. But when running it under the PHP 7.4 environment, the application throws a 502 Bad Gateway error.
Could you please provide guidance on how to correctly install and configure Yii2 2.0.49 to ensure full compatibility with PHP 7.4?

Package version

2.0.49

PHP version

7.4

[samdark]

Any stacktrace?