Room: Auditorium Presenter: Lauri Eskola Description: Drupal's theme system is too complex to use. Doing basic tasks such as changing markup, preprocessing data and attaching new CSS and JavaScript takes a lot of knowledge. Drupal theme system, which is over a decade old system also fails to support some of the modern software engineering practices applied commonly these days, such as semver and component driven development. Support to both of these has been added as an hacked-on after-thought, that have big downsides. On this session, I will give an overview of what changes has been made prior to Drupal 9 to tackle some of these issues. I will also walk through some of the ideas on how we could further improve the frontend development experience during the development of Drupal 9 minor releases.