On his site Fabien Potencier has posted an article about the next major release of the Symfony framework - version 4 - and how it will allow for the "composition" of your applications rather than some of the current methods.

Symfony 3.0 was boring, a cleaned-up version of the Symfony 2.8 version. Symfony 4.0 will be different: Symfony 4.0 = Symfony 3.4 - deprecated features + a new way to develop applications

There is another way to think about a new major version though: Symfony 4.0 = Symfony 3.0 + all features added in 3.x - deprecated features + a new way to develop applications

He goes through some of his thinking process around some of these changes and the "day-to-day experience" of managing a Symfony application. Specifically he suggests that:

• Installing a Bundle is too cumbersome
• Removing a Bundle is even more cumbersome
• The Symfony Standard Edition is not good enough
• No Distribution Ecosystem

He ends the post with a look at what he sees as the ideal ecosystem for the framework and where Symfony Flex fits into the picture (example project here).

Symfony Flex is going to be the default way to manage Symfony 4 applications. But Symfony Flex will be available as an option to manage Symfony 3.3 and 3.4 applications as well! That said, we might need to break backward compatibility between now and the launch of Symfony 4. Consider Symfony Flex as alpha before Symfony 4.