XF 2.3 Error upgrading to 2.3.0

[Talionic]

Got the following server error after upgrading: Error: Call to undefined method XF\Style::getVariation() src/XF/CssRenderer.php:105

#0 src/XF/CssRenderer.php(80): XF\CssRenderer->setStyle(Object(XF\Style))
#1 src/XF/Pub/View/ServiceWorker/Offline.php(22): XF\CssRenderer->__construct(Object(XF\Pub\App), Object(XF\Template\Templater), NULL)
#2 src/XF/Mvc/Renderer/AbstractRenderer.php(91): XF\Pub\View\ServiceWorker\Offline->renderHtml()
#3 src/XF/Mvc/Renderer/Html.php(47): XF\Mvc\Renderer\AbstractRenderer->renderViewObject('XF:ServiceWorke...', 'public:service_...', Array)
#4 src/XF/Mvc/Dispatcher.php(460): XF\Mvc\Renderer\Html->renderView('XF:ServiceWorke...', 'public:service_...', Array)
#5 src/XF/Mvc/Dispatcher.php(442): XF\Mvc\Dispatcher->renderView(Object(XF\Mvc\Renderer\Html), Object(XF\Mvc\Reply\View))
#6 src/XF/Mvc/Dispatcher.php(402): XF\Mvc\Dispatcher->renderReply(Object(XF\Mvc\Renderer\Html), Object(XF\Mvc\Reply\View))
#7 src/XF/Mvc/Dispatcher.php(60): XF\Mvc\Dispatcher->render(Object(XF\Mvc\Reply\View), 'html')
#8 src/XF/App.php(2485): XF\Mvc\Dispatcher->run()
#9 src/XF.php(524): XF\App->run()
#10 index.php(23): XF::runApp('XF\\Pub\\App')
#11 {main}

What does it mean?