What does it mean for your projects based on Shopsys Framework?
Your project will download automatically a version 2 of Composer, because the script installing Composer programmatically will always download the latest version. (script is located in docker/php-fpm/docker-install-composer)
It’s possible for your new builds to fail with the new version. Composer 2 includes support for parallel downloads, and it is now not necessary (nor possible) to continue using the hirak/prestissimo plugin. You will need to remove this plugin from Dockerfile. You can find inspiration here – https://github.com/shopsys/shopsys/pull/2089.
You will probably need to update your dependencies with the …
… command, because some packages (for example symfony/flex) added support for Composer 2 in versions you may not have installed yet.
In case you need to fallback to Composer 1, you can update the docker/php-fpm/docker-install-composer file