New in Symfony 3.4: Form improvements

Symfony 3.4 adds new HTML5 form types ("tel" and "color"), new options for TimezoneType and support for callbacks in the delete_empty option.

New in Symfony 3.4: Defining compiler passes in the kernel

In Symfony 3.4, the kernel of the application can implement CompilerPassInterface to define a compiler pass in it.

New in Symfony 3.4: Bootstrap 4 form theme

Symfony 3.4 adds a new form theme for Bootstrap 4, the most popular front-end component library.

New in Symfony 3.4: Argon2i password hasher

Symfony 3.4 includes an Argon2i password hasher , a modern alternative to Bcrypt natively supported by PHP 7.2.

New in Symfony 3.4: Default request context for assets

Symfony 3.4 provides new configuration options so you can generate the right URL for assets out of the HTTP context, for example in a command console.

New in Symfony 3.4: Deprecated bundle inheritance

Symfony 3.4 deprecates bundle inheritance, but Symfony still provides lots of alternatives to override the resources of third-party bundles in your application.

New in Symfony 3.4: Better code coverage reports

Symfony 3.4 adds a new CoverageListener to the PHPUnit Bridge component to create more precise code coverage reports.

New in Symfony 3.4: PHP-based configuration for services and routes

Symfony 3.4 introduces a new (optional) PHP-based configuration format to define routes and services using a fluent interface.

New in Symfony 3.4: Advanced environment variables

Symfony 3.4 allows to define the data type of the value stored in environment variables and also defines some operators to transform their values before using them.

New in Symfony 3.4: Improved comparison constraints

In Symfony 3.4, comparison constraints can get the value of any other property without having to define a full expression.