Problem/Motivation The signature of the "Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher::dispatch()" method should be updated to "dispatch($event, string $eventName = null)", not doing so is deprecated since Symfony 4.3. Calling the "Symfony\Component\EventDispatcher\EventDispatcherInterface::dispatch()" method with the event name as first argument is deprecated since Symfony 4.3, pass it second and provide the event object first instead. Related https://symfony.com/blog/new-in-symfony-4-3-simpler-event-dispatching

Validation: Validation is a very common task in web applications. Data entered in forms needs to be validated. Data also needs to be validated before it is written into a database or passed to a web s...

How to Use the Serializer: Symfony provides a serializer to serialize/deserialize to and from objects and different formats (e.g. JSON or XML). Before using it, read the Serializer component docs to g...

How to Dynamically Modify Forms Using Form Events: Often times, a form can't be created statically. In this article, you'll learn how to customize your form based on three common use-cases:  Customizi...