diff --git a/content-grid.php b/content-grid.php
index 8d063e9..c749b45 100644
--- a/content-grid.php
+++ b/content-grid.php
@@ -8,7 +8,7 @@
 				<?php if ( has_post_thumbnail() ): ?>
 					<?php the_post_thumbnail('featureon-medium'); ?>
 				<?php elseif ( get_theme_mod('placeholder','on') == 'on' ): ?>
-					<img src="<?php echo get_template_directory_uri(); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
+					<img src="<?php echo esc_url( get_template_directory_uri() ); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
 				<?php endif; ?>
 				<?php if ( has_post_format('video') && !is_sticky() ) echo'<span class="thumb-icon"><i class="fas fa-play"></i></span>'; ?>
 				<?php if ( has_post_format('audio') && !is_sticky() ) echo'<span class="thumb-icon"><i class="fas fa-volume-up"></i></span>'; ?>
diff --git a/content-highlight.php b/content-highlight.php
index 0b65b14..1da1ff4 100644
--- a/content-highlight.php
+++ b/content-highlight.php
@@ -7,7 +7,7 @@
 		<?php $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'featureon-medium' ); ?>
 		<img src="<?php echo $image[0]; ?>" alt="<?php the_title_attribute(); ?>" />
 	<?php elseif ( get_theme_mod('placeholder','on') == 'on' ): ?>
-		<img src="<?php echo get_template_directory_uri(); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
+		<img src="<?php echo esc_url( get_template_directory_uri() ); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
 	<?php endif; ?>
 	
 	<div class="featured-content">
diff --git a/content-list.php b/content-list.php
index b29fd56..4c1659f 100644
--- a/content-list.php
+++ b/content-list.php
@@ -8,7 +8,7 @@
 				<?php if ( has_post_thumbnail() ): ?>
 					<?php the_post_thumbnail('featureon-square'); ?>
 				<?php elseif ( get_theme_mod('placeholder','on') == 'on' ): ?>
-					<img src="<?php echo get_template_directory_uri(); ?>/img/thumb-square.png" alt="<?php the_title_attribute(); ?>" />
+					<img src="<?php echo esc_url( get_template_directory_uri() ); ?>/img/thumb-square.png" alt="<?php the_title_attribute(); ?>" />
 				<?php endif; ?>
 				<?php if ( has_post_format('video') && !is_sticky() ) echo'<span class="thumb-icon"><i class="fas fa-play"></i></span>'; ?>
 				<?php if ( has_post_format('audio') && !is_sticky() ) echo'<span class="thumb-icon"><i class="fas fa-volume-up"></i></span>'; ?>
diff --git a/content.php b/content.php
index 882bb73..6e4f0cd 100644
--- a/content.php
+++ b/content.php
@@ -8,7 +8,7 @@
 				<?php if ( has_post_thumbnail() ): ?>
 					<?php the_post_thumbnail('featureon-medium'); ?>
 				<?php elseif ( get_theme_mod('placeholder','on') == 'on' ): ?>
-					<img src="<?php echo get_template_directory_uri(); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
+					<img src="<?php echo esc_url( get_template_directory_uri() ); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
 				<?php endif; ?>
 				<?php if ( has_post_format('video') && !is_sticky() ) echo'<span class="thumb-icon"><i class="fas fa-play"></i></span>'; ?>
 				<?php if ( has_post_format('audio') && !is_sticky() ) echo'<span class="thumb-icon"><i class="fas fa-volume-up"></i></span>'; ?>
diff --git a/inc/related-posts.php b/inc/related-posts.php
index 81f8ed6..019cc04 100644
--- a/inc/related-posts.php
+++ b/inc/related-posts.php
@@ -17,7 +17,7 @@
 					<?php if ( has_post_thumbnail() ): ?>
 						<?php the_post_thumbnail('featureon-medium'); ?>
 					<?php elseif ( get_theme_mod('placeholder','on') == 'on' ): ?>
-						<img src="<?php echo get_template_directory_uri(); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
+						<img src="<?php echo esc_url( get_template_directory_uri() ); ?>/img/thumb-medium.png" alt="<?php the_title_attribute(); ?>" />
 					<?php endif; ?>
 					<?php if ( has_post_format('video') && !is_sticky() ) echo'<span class="thumb-icon small"><i class="fas fa-play"></i></span>'; ?>
 					<?php if ( has_post_format('audio') && !is_sticky() ) echo'<span class="thumb-icon small"><i class="fas fa-volume-up"></i></span>'; ?>
diff --git a/style.css b/style.css
index bad215b..a1df175 100644
--- a/style.css
+++ b/style.css
@@ -4,6 +4,7 @@ Theme URI: http://alx.media/themes/featureon/
 Version: 2.3.9
 Requires at least: 5.0
 Requires PHP: 5.6
+Tested up to: 5.5
 Description: <a href="http://alx.media/themes/featureon/">Featureon</a> is a responsive 100% high resolution theme for blogs and magazines. Unique toggle sidebars give a great browsing and reading experience on both tablet and mobile. The feature list is long: Unlimited accent colors, unlimited widget areas, 0-2 sidebars to the left or right that can be uniquely specified for each page or post, 300px / 300px fixed width sidebars, 0-4 footer widget columns, almost zero layout images, related posts and post nav, featured stories and carousel, 5 post formats, good SEO, 2 flexible custom widgets, localisation support, social links, logo upload and many more useful admin panel features.
 Author: Alexander Agnarson
 Author URI: http://alx.media