Call to undefined method Drupal\\Core\\File\\FileSystem::scanDirectory()

Hello,
i just tried to update to -beta2 and i see WSOD. I'm still running Drupal 8.7.11 - is that a problem?

[Thu Feb 20 12:29:44.399025 2020] [php7:notice] [pid 21295] [client 10.0.0.1:45465] Error: Call to undefined method Drupal\\Core\\File\\FileSystem::scanDirectory() in /home/xxx/modules/high_contrast/src/HighContrastConfigOverride.php on line 123 #0 /home/xxx/modules/high_contrast/src/HighContrastConfigOverride.php(65): Drupal\\high_contrast\\HighContrastConfigOverride->getHighContrastLogo()\n#1 /var/www/html/drupal8/core/lib/Drupal/Core/Config/ConfigFactory.php(209): Drupal\\high_contrast\\HighContrastConfigOverride->loadOverrides(Array)\n#2 /var/www/html/drupal8/core/lib/Drupal/Core/Config/ConfigFactory.php(169): Drupal\\Core\\Config\\ConfigFactory->loadOverrides(Array)\n#3 /var/www/html/drupal8/core/lib/Drupal/Core/Config/ConfigFactory.php(104): Drupal\\Core\\Config\\ConfigFactory->doLoadMultiple(Array, true)\n#4 /var/www/html/drupal8/core/lib/Drupal/Core/Config/ConfigFactory.php(89): Drupal\\Core\\Config\\ConfigFactory->doGet('system.theme.gl...')\n#5 /var/www/html/drupal8/core/lib/Drupal.php(379): Drupal\\Core\\Config\\ConfigFactory->get('system.theme.gl...')\n#6 /var/www/html/drupal8/core/includes/theme.inc(319): Drupal::config('system.theme.gl...')\n#7 /var/www/html/drupal8/core/modules/system/system.module(607): theme_get_setting('features.favico...')\n#8 /var/www/html/drupal8/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php(297): system_page_attachments(Array)\n#9 /var/www/html/drupal8/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php(273): Drupal\\Core\\Render\\MainContent\\HtmlRenderer->invokePageAttachmentHooks(Array)\n#10 /var/www/html/drupal8/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php(117): Drupal\\Core\\Render\\MainContent\\HtmlRenderer->prepare(Array, Object(Symfony\\Component\\HttpFoundation\\Request), Object(Drupal\\Core\\Routing\\CurrentRouteMatch))\n#11 /var/www/html/drupal8/core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php(90): Drupal\\Core\\Render\\MainContent\\HtmlRenderer->renderResponse(Array, Object(Symfony\\Component\\HttpFoundation\\Request), Object(Drupal\\Core\\Routing\\CurrentRouteMatch))\n#12 [internal function]: Drupal\\Core\\EventSubscriber\\MainContentViewSubscriber->onViewRenderArray(Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForControllerResultEvent), 'kernel.view', Object(Drupal\\Component\\EventDispatcher\\ContainerAwareEventDispatcher))\n#13 /var/www/html/drupal8/core/lib/Drupal/Component/EventDispatcher/ContainerAwareEventDispatcher.php(111): call_user_func(Array, Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForControllerResultEvent), 'kernel.view', Object(Drupal\\Component\\EventDispatcher\\ContainerAwareEventDispatcher))\n#14 /var/www/html/drupal8/vendor/symfony/http-kernel/HttpKernel.php(156): Drupal\\Component\\EventDispatcher\\ContainerAwareEventDispatcher->dispatch('kernel.view', Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForControllerResultEvent))\n#15 /var/www/html/drupal8/vendor/symfony/http-kernel/HttpKernel.php(68): Symfony\\Component\\HttpKernel\\HttpKernel->handleRaw(Object(Symfony\\Component\\HttpFoundation\\Request), 2)\n#16 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\\Component\\HttpKernel\\HttpKernel->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#17 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\\Core\\StackMiddleware\\Session->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#18 /var/www/html/drupal8/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\\Core\\StackMiddleware\\KernelPreHandle->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#19 /var/www/html/drupal8/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\\page_cache\\StackMiddleware\\PageCache->pass(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#20 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\\page_cache\\StackMiddleware\\PageCache->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#21 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\\Core\\StackMiddleware\\ReverseProxyMiddleware->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#22 /var/www/html/drupal8/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\\Core\\StackMiddleware\\NegotiationMiddleware->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2, true)\n#23 /var/www/html/drupal8/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php(166): Stack\\StackedHttpKernel->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 2)\n#24 /var/www/html/drupal8/core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php(112): Drupal\\Core\\EventSubscriber\\DefaultExceptionHtmlSubscriber->makeSubrequest(Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForExceptionEvent), '/system/403', 403)\n#25 /var/www/html/drupal8/core/lib/Drupal/Core/EventSubscriber/HttpExceptionSubscriberBase.php(109): Drupal\\Core\\EventSubscriber\\DefaultExceptionHtmlSubscriber->on403(Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForExceptionEvent))\n#26 [internal function]: Drupal\\Core\\EventSubscriber\\HttpExceptionSubscriberBase->onException(Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForExceptionEvent), 'kernel.exceptio...', Object(Drupal\\Component\\EventDispatcher\\ContainerAwareEventDispatcher))\n#27 /var/www/html/drupal8/core/lib/Drupal/Component/EventDispatcher/ContainerAwareEventDispatcher.php(111): call_user_func(Array, Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForExceptionEvent), 'kernel.exceptio...', Object(Drupal\\Component\\EventDispatcher\\ContainerAwareEventDispatcher))\n#28 /var/www/html/drupal8/vendor/symfony/http-kernel/HttpKernel.php(228): Drupal\\Component\\EventDispatcher\\ContainerAwareEventDispatcher->dispatch('kernel.exceptio...', Object(Symfony\\Component\\HttpKernel\\Event\\GetResponseForExceptionEvent))\n#29 /var/www/html/drupal8/vendor/symfony/http-kernel/HttpKernel.php(79): Symfony\\Component\\HttpKernel\\HttpKernel->handleException(Object(Drupal\\Core\\Http\\Exception\\CacheableAccessDeniedHttpException), Object(Symfony\\Component\\HttpFoundation\\Request), 1)\n#30 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\\Component\\HttpKernel\\HttpKernel->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#31 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\\Core\\StackMiddleware\\Session->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#32 /var/www/html/drupal8/core/modules/page_cache/src/StackMiddleware/PageCache.php(106): Drupal\\Core\\StackMiddleware\\KernelPreHandle->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#33 /var/www/html/drupal8/core/modules/page_cache/src/StackMiddleware/PageCache.php(85): Drupal\\page_cache\\StackMiddleware\\PageCache->pass(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#34 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\\page_cache\\StackMiddleware\\PageCache->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#35 /var/www/html/drupal8/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\\Core\\StackMiddleware\\ReverseProxyMiddleware->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#36 /var/www/html/drupal8/vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\\Core\\StackMiddleware\\NegotiationMiddleware->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#37 /var/www/html/drupal8/core/lib/Drupal/Core/DrupalKernel.php(693): Stack\\StackedHttpKernel->handle(Object(Symfony\\Component\\HttpFoundation\\Request), 1, true)\n#38 /var/www/html/drupal8/index.php(19): Drupal\\Core\\DrupalKernel->handle(Object(Symfony\\Component\\HttpFoundation\\Request))\n#39 {main}