Creating a New Project Based on an Unstable Symfony Version

Suppose that Symfony2.7 version hasn't been released yet and you want to create

Suppose thattheSymfony4.0 version hasn't been released yet and you want to create

a new project to test its features. First,:doc:`install the Composer</setup/composer>`

package manager. Then, open a command console, enter your project's directory and

execute the following command:

..code-block::terminal

Once the command finishes its execution, you'll have a new Symfony project created

in the ``my_project/`` directory and based on the most recent code found in the

``2.7`` branch.

If you want to test a beta version, use ``beta`` as the value of the ``stability``

option:

..code-block::terminal

in the ``my_project/`` directory.

Upgrading your Project to an Unstable Symfony Version

Suppose again that Symfony2.7 hasn't been released yet and you want to upgrade

Suppose again that Symfony4.0 hasn't been released yet and you want to upgrade

an existing application to test that your project works with it.

First, open the ``composer.json`` file located in the root directory of your

project. Then, edit the value ofthe version defined forthe ``symfony/symfony``

dependency as follows:

project. Then, edit the value ofall ofthe ``symfony/*`` libraries to the

new version and change your ``minimum-stability`` to ``beta``:

..code-block::json

..code-block::diff

Finally, open a command console, enter your project directory and execute the

following command to update your project dependencies:

You can also use set ``minimum-stability`` to ``dev``, or omit this line

entirely, and opt into your stability on each package by using constraints

like ``4.0.*@beta``.

Finally, from aterminal, update your project's dependencies:

If you prefer to test a Symfony beta version, replace the ``"2.7.*@dev"`` constraint

by ``"2.7.0-beta1"`` to install a specific beta number or ``2.7.*@beta`` to get

the most recent beta version.

After upgrading the Symfony version, read the:ref:`Symfony Upgrading Guide<upgrade-major-symfony-deprecations>`

to learn how you should proceed to update your application's code in case the new