---
id: eaf00cf5-efb7-4f53-b721-4f0592671400
title: Symfony 4.0
---

# What's new

## Profiler

-   [Validator information in the Symfony
    profiler](20201109140046-validator_information_in_the_symfony_profiler)
-   [User impersonation in debug
    toolbar](20201109143336-symfony_user_impersonation_in_debug_toolbar)

## Validation

### Constraints

-   [ExpressionLanguage
    Constraint](20201109150640-expressionlanguage_constraint)
-   [Groups support for Valid
    constraint](20201109145724-groups_support_for_valid_constraint)

## Annotations

-   [Prefix all controller route
    names](20201109142351-prefix_all_controller_route_names)

## Subscribers

-   [Subscribing to events in the micro
    kernel](20201109150109-subscribing_to_events_in_the_micro_kernel)

## Components

### Stopwatch

-   [reset() method](20201109141042-reset_method)
-   [Microseconds support](20201109141116-microseconds_support)

### Command

-   [Lazy Commands](20201109141540-lazy_commands)

### Translation

-   [XLIFF 2.0](20201109142907-xliff_2_0)

### Guard

-   [getCredentials() responsibilities
    split](20201109152527-getcredentials_responsibilities_split)

## Sessions

-   [Lazy Sessions](20201109151019-lazy_sessions)

## Commands

-   [debug:autowiring](20201109151937-debug_autowiring)
-   [debug:form](20201109152714-debug_form)

## Autowiring

-   [Local Service Binding](20201109153159-local_service_binding)