diff --git a/content-sample/_meta.md b/content-sample/_meta.md
index d18f051..09dad93 100644
--- a/content-sample/_meta.md
+++ b/content-sample/_meta.md
@@ -1,5 +1,5 @@
 ---
-Logo: %theme_url%/img/pico-white.svg
+Logo: '%theme_url%/img/pico-white.svg'
 Tagline: Making the web easy.
 Social:
     - title: Visit us on GitHub
diff --git a/lib/Pico.php b/lib/Pico.php
index 4b3a450..d3036d5 100644
--- a/lib/Pico.php
+++ b/lib/Pico.php
@@ -2102,12 +2102,12 @@ class Pico
         if ($this->twig === null) {
             $twigConfig = $this->getConfig('twig_config');
 
-            $twigLoader = new Twig_Loader_Filesystem($this->getThemesDir() . $this->getTheme());
-            $this->twig = new Twig_Environment($twigLoader, $twigConfig);
+            $twigLoader = new \Twig\Loader\FilesystemLoader($this->getThemesDir() . $this->getTheme());
+            $this->twig = new \Twig\Environment($twigLoader, $twigConfig);
             $this->twig->addExtension(new PicoTwigExtension($this));
 
             if (!empty($twigConfig['debug'])) {
-                $this->twig->addExtension(new Twig_Extension_Debug());
+                $this->twig->addExtension(new Twig\Extension\DebugExtension());
             }
 
             // register content filter
@@ -2115,7 +2115,7 @@ class Pico
             // this is the reason why we can't register this filter as part of PicoTwigExtension
             $pico = $this;
             $pages = &$this->pages;
-            $this->twig->addFilter(new Twig_SimpleFilter(
+            $this->twig->addFilter(new \Twig\TwigFilter(
                 'content',
                 function ($page) use ($pico, &$pages) {
                     if (isset($pages[$page])) {
@@ -2156,7 +2156,7 @@ class Pico
             'theme_url' => $this->getConfig('themes_url') . $this->getTheme(),
             'site_title' => $this->getConfig('site_title'),
             'meta' => $this->meta,
-            'content' => new Twig_Markup($this->content, 'UTF-8'),
+            'content' => new \Twig\Markup($this->content, 'UTF-8'),
             'pages' => $this->pages,
             'previous_page' => $this->previousPage,
             'current_page' => $this->currentPage,
diff --git a/lib/PicoTwigExtension.php b/lib/PicoTwigExtension.php
index d87a6e1..1f170f6 100644
--- a/lib/PicoTwigExtension.php
+++ b/lib/PicoTwigExtension.php
@@ -67,20 +67,20 @@ class PicoTwigExtension extends Twig_Extension
      *
      * @see Twig_ExtensionInterface::getFilters()
      *
-     * @return Twig_SimpleFilter[] array of Pico's Twig filters
+     * @return \Twig\TwigFilter[] array of Pico's Twig filters
      */
     public function getFilters()
     {
         return array(
-            'markdown' => new Twig_SimpleFilter(
+            'markdown' => new \Twig\TwigFilter(
                 'markdown',
                 array($this, 'markdownFilter'),
                 array('is_safe' => array('html'))
             ),
-            'map' => new Twig_SimpleFilter('map', array($this, 'mapFilter')),
-            'sort_by' => new Twig_SimpleFilter('sort_by', array($this, 'sortByFilter')),
-            'link' => new Twig_SimpleFilter('link', array($this->pico, 'getPageUrl')),
-            'url' => new Twig_SimpleFilter('url', array($this->pico, 'substituteUrl'))
+            'map' => new \Twig\TwigFilter('map', array($this, 'mapFilter')),
+            'sort_by' => new \Twig\TwigFilter('sort_by', array($this, 'sortByFilter')),
+            'link' => new \Twig\TwigFilter('link', array($this->pico, 'getPageUrl')),
+            'url' => new \Twig\TwigFilter('url', array($this->pico, 'substituteUrl'))
         );
     }