Update IvoryCKEditorBundle to version 4.x.
The old {{ ckeditor_replace() }} twig function has been replaced by {{ ckeditor_widget() }}.
This introduce the new inline option of CKEditor plugin.
All related changes are available here [IvoryCKEditorUPGRADE] (https://github.com/egeloen/IvoryCKEditorBundle/blob/master/UPGRADE.md#25-to-30)