We are going to deploy the new yiiframework.com website on March 23, 2018 from 8:00 to 12:00 UTC.
Website and Yii documentation will not be available in this time frame. Check the news for more details.
When building PHP web applications you usually have to take care about defining and providing a consistent development and production environment for your team. This includes your application packages, PHP-extensions, database servers and often further components such as a mail server or workers.