This is a major releases that introduces many smaller features, dozens of bug fixes and a couple of infrastructure changes (an upgrade to `webpack@4`, simplified structure of the build repository). Additionally, the `DecoupledEditor#element` property was renamed to `DecoupledEditor#sourceElement`.
If you maintain a [custom build of CKEditor 5](https://docs.ckeditor.com/ckeditor5/latest/builds/guides/development/custom-builds.html) or [integrate CKEditor 5 from source](https://docs.ckeditor.com/ckeditor5/latest/builds/guides/integration/advanced-setup.html#scenario-2-building-from-source), we recommend reading the [migration guide](https://github.com/ckeditor/ckeditor5/issues/1136).
* Changed the build structure. TODO. Closes [ckeditor/ckeditor5#1038](https://github.com/ckeditor/ckeditor5/issues/1038). ([cd72eca](https://github.com/ckeditor/ckeditor5-build-decoupled-document/commit/cd72eca))
* Changed the structure of the build repository. Closes [ckeditor/ckeditor5#1038](https://github.com/ckeditor/ckeditor5/issues/1038). ([cd72eca](https://github.com/ckeditor/ckeditor5-build-decoupled-document/commit/cd72eca))
* Updated `webpack` to version 4. ([dfdde57](https://github.com/ckeditor/ckeditor5-build-decoupled-document/commit/dfdde57))
* Updated `webpack` to version 4 (applies to custom builds only). ([dfdde57](https://github.com/ckeditor/ckeditor5-build-decoupled-document/commit/dfdde57))
### BREAKING CHANGES
### BREAKING CHANGES
* CKEditor 5 environment was updated to use `webpack@4`. `webpack@4` introduced major changes in its configuration and plugin system. CKEditor 5 tools and build configuration were updated to work with `webpack@4` now and will not work with `webpack@3.
If you maintain a custom build, we recommend reading the [migration guide](https://github.com/ckeditor/ckeditor5/issues/1136). Closes [ckeditor/ckeditor5#1038](https://github.com/ckeditor/ckeditor5/issues/1038).
* CKEditor 5 environment was updated to use `webpack@4`. `webpack@4` introduced major changes in its configuration and plugin system. CKEditor 5 tools and build configuration were updated to work with `webpack@4` and will not work with `webpack@3`.
* The structure of the build repository was changed. The `build-config.js` file was removed and the build configuration is now kept only in the `src/ckeditor.js` file.