The 3 Greatest News with Symfony 4.3

Last week, the SensioLabs team enjoyed a “noon-training, led by Alex Rock on the new features of Symfony 4.3 released on May 30th. This noon-training was also the opportunity to think about the benefits of technology watch.

“Noon-trainings” are trainings dedicated to SensioLabs internal staff. Once a week, SensioLabs University sets up a one-hour training. All SensioLabs team members (and of course remote developers) is invited to keep learning and developing new skills.

This week, we focused of Symfony 4.3 new features. We had the opportunity to review what has changed with this new minor version of Symfony and in particular its 3 main new features.


Among the new features of the 4.3 version, the Mailer component is surely the one that generated the more buzz with Fabien’s keynote at SymfonyLive Paris 2019! Worthy heir of Swiftmailer, it is oriented towards simplicity and good practices. Be careful however, Mailer is still experimental: the code will not necessarily be compatible with the next stable version.

HTTP Client is already used in production. Several benchmarks have shown high performance gains thanks to this new component that combines simplification with the objective of a uniform customer for everyone. Please note that the Mercure protocol will soon be compatible with this component.

The Mime Component is a little less known, but very effective and adapts to contemporary use cases. Mime manages the writing of emails, allows to create and customize emails, in addition to Mailer. Native integration with Twig is very successful and the documentation is promising!


Other changes also drew our attention including:

  • Extraction of file translations from PHP by Yonel Ceruto.
  • Improvement of the Intl component and timezones by Roland Franssen.
  • A new NativePasswordEncoder class to replace other password encoders.
  • Improvements to the Form component, including the data mappers and the “debug: form” command.
  • Additional transports for Messenger (Doctrine, Redis and Memory), and another specific for backing up messages and failing messages later.
  • 3 new versions of Flex including Sylius plugin management.
  • Many changes on the Webpack Encore recipe.
  • A contribution from Renan, arrived at SensioLabs few months ago, thanks to him 😉

Finally, this new version has no CVE, no security critical bug.


Keep in mind that all this information is available on in the “News” section. You can find all the new features of Symfony 4.3 (there are many!) in Fabien’s post “Symfony 4.3 curated new features“.

Information on versions can be found in the “Living in the Edge” category. You will be able to find everything on the new versions since Symfony 2.2! it’s the perfect tool for keeping up with Symfony.

Technology watch is essential for anyone working in the development industry because web technologies evolve very fast, especially for Symfony. You should update regularly, otherwise you can be quickly outdated. Technology watch is not the enemy of productivity, on the opposite. Spending time to technology watch, the quality of your project will improve and you can suggest the most adapted solutions.

SensioLabs University will regularly hold technology watch sessions on Symfony so that the SensioLabs team precisely follows the evolution of the framework and continues to increase its skills on a regular basis.