diff --git a/content.php b/content.php
index 65ca1f3..ebe31e5 100644
--- a/content.php
+++ b/content.php
@@ -8,7 +8,7 @@
 				<?php if ( has_post_thumbnail() ): ?>
 					<?php the_post_thumbnail('gridzone-medium-h'); ?>
 				<?php else: ?>
-					<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 2a62697..9511556 100644
--- a/inc/related-posts.php
+++ b/inc/related-posts.php
@@ -12,7 +12,7 @@
 					<?php if ( has_post_thumbnail() ): ?>
 						<?php the_post_thumbnail('gridzone-medium'); ?>
 					<?php else: ?>
-						<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/style.css b/style.css
index e2457e0..851d9be 100644
--- a/style.css
+++ b/style.css
@@ -4,6 +4,7 @@ Theme URI: http://alx.media/themes/gridzone/
 Version: 1.2.4
 Requires at least: 5.0
 Requires PHP: 5.6
+Tested up to: 5.5
 Description: <a href="http://alx.media/themes/gridzone/">Gridzone</a> is a flexible portfolio theme with plenty of options. It is optimized for all devices and built to work with blocks. You can choose between light and dark theme, widget sidebar to the left or right - or no sidebar at all. Demo: http://demo.alx.media/x/?theme=Gridzone
 Author: Alexander Agnarson
 Author URI: http://alx.media