Error message

• Deprecated function: fwrite(): Passing null to parameter #2 ($data) of type string is deprecated in Masterminds\HTML5\Serializer\OutputRules->wr() (line 451 of /code/vendor/masterminds/html5/src/HTML5/Serializer/OutputRules.php).

  Masterminds\HTML5\Serializer\OutputRules->wr() (Line: 308)
  Masterminds\HTML5\Serializer\OutputRules->namespaceAttrs() (Line: 326)
  Masterminds\HTML5\Serializer\OutputRules->openTag() (Line: 229)
  Masterminds\HTML5\Serializer\OutputRules->element() (Line: 93)
  Masterminds\HTML5\Serializer\Traverser->node() (Line: 77)
  Masterminds\HTML5\Serializer\Traverser->walk() (Line: 322)
  Drupal\Component\Utility\Html::serialize() (Line: 280)
  Drupal\ckeditor5_premium_features\Plugin\Filter\FilterCollaboration->doProcess() (Line: 232)
  Drupal\ckeditor5_premium_features\Plugin\Filter\FilterCollaboration->process() (Line: 123)
  Drupal\filter\Element\ProcessedText::preRenderText()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 875)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 974)
  Drupal\views\Plugin\views\field\EntityField->render_item() (Line: 259)
  Drupal\search_api\Plugin\views\field\SearchApiEntityField->render_item() (Line: 1214)
  Drupal\views\Plugin\views\field\FieldPluginBase->advancedRender() (Line: 238)
  template_preprocess_views_view_field()
  call_user_func_array() (Line: 261)
  Drupal\Core\Theme\ThemeManager->render() (Line: 491)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 1797)
  Drupal\views\Plugin\views\field\FieldPluginBase->theme() (Line: 770)
  Drupal\views\Plugin\views\style\StylePluginBase->elementPreRenderRow()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 875)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 709)
  Drupal\views\Plugin\views\style\StylePluginBase->renderFields() (Line: 575)
  Drupal\views\Plugin\views\style\StylePluginBase->renderGrouping() (Line: 463)
  Drupal\views\Plugin\views\style\StylePluginBase->render() (Line: 2177)
  Drupal\views\Plugin\views\display\DisplayPluginBase->render() (Line: 1593)
  Drupal\views\ViewExecutable->render() (Line: 201)
  Drupal\views\Plugin\views\display\Page->execute() (Line: 1690)
  Drupal\views\ViewExecutable->executeDisplay() (Line: 81)
  Drupal\views\Element\View::preRenderViewElement()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 875)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 238)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 638)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 231)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (Line: 128)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse() (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray() (Line: 97)
  Drupal\tracer\EventDispatcher\TraceableEventDispatcher->dispatch() (Line: 186)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
  Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 201)
  Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 138)
  Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 87)
  Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 38)
  Drupal\tracer\StackMiddleware\TracesMiddleware->handle() (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
  Drupal\Core\DrupalKernel->handle() (Line: 19)
  

• Deprecated function: fwrite(): Passing null to parameter #2 ($data) of type string is deprecated in Masterminds\HTML5\Serializer\OutputRules->wr() (line 451 of /code/vendor/masterminds/html5/src/HTML5/Serializer/OutputRules.php).

  Masterminds\HTML5\Serializer\OutputRules->wr() (Line: 308)
  Masterminds\HTML5\Serializer\OutputRules->namespaceAttrs() (Line: 326)
  Masterminds\HTML5\Serializer\OutputRules->openTag() (Line: 229)
  Masterminds\HTML5\Serializer\OutputRules->element() (Line: 93)
  Masterminds\HTML5\Serializer\Traverser->node() (Line: 77)
  Masterminds\HTML5\Serializer\Traverser->walk() (Line: 322)
  Drupal\Component\Utility\Html::serialize() (Line: 280)
  Drupal\ckeditor5_premium_features\Plugin\Filter\FilterCollaboration->doProcess() (Line: 232)
  Drupal\ckeditor5_premium_features\Plugin\Filter\FilterCollaboration->process() (Line: 123)
  Drupal\filter\Element\ProcessedText::preRenderText()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 875)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 974)
  Drupal\views\Plugin\views\field\EntityField->render_item() (Line: 259)
  Drupal\search_api\Plugin\views\field\SearchApiEntityField->render_item() (Line: 1214)
  Drupal\views\Plugin\views\field\FieldPluginBase->advancedRender() (Line: 238)
  template_preprocess_views_view_field()
  call_user_func_array() (Line: 261)
  Drupal\Core\Theme\ThemeManager->render() (Line: 491)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 1797)
  Drupal\views\Plugin\views\field\FieldPluginBase->theme() (Line: 770)
  Drupal\views\Plugin\views\style\StylePluginBase->elementPreRenderRow()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 875)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 709)
  Drupal\views\Plugin\views\style\StylePluginBase->renderFields() (Line: 575)
  Drupal\views\Plugin\views\style\StylePluginBase->renderGrouping() (Line: 463)
  Drupal\views\Plugin\views\style\StylePluginBase->render() (Line: 2177)
  Drupal\views\Plugin\views\display\DisplayPluginBase->render() (Line: 1593)
  Drupal\views\ViewExecutable->render() (Line: 201)
  Drupal\views\Plugin\views\display\Page->execute() (Line: 1690)
  Drupal\views\ViewExecutable->executeDisplay() (Line: 81)
  Drupal\views\Element\View::preRenderViewElement()
  call_user_func_array() (Line: 113)
  Drupal\Core\Render\Renderer->doTrustedCallback() (Line: 875)
  Drupal\Core\Render\Renderer->doCallback() (Line: 432)
  Drupal\Core\Render\Renderer->doRender() (Line: 248)
  Drupal\Core\Render\Renderer->render() (Line: 238)
  Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 638)
  Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 231)
  Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (Line: 128)
  Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse() (Line: 90)
  Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray() (Line: 97)
  Drupal\tracer\EventDispatcher\TraceableEventDispatcher->dispatch() (Line: 186)
  Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
  Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
  Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
  Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
  Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 201)
  Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 138)
  Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 87)
  Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
  Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 38)
  Drupal\tracer\StackMiddleware\TracesMiddleware->handle() (Line: 51)
  Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
  Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
  Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 741)
  Drupal\Core\DrupalKernel->handle() (Line: 19)