diff --git a/core/includes/common.inc b/core/includes/common.inc
index d3310ad..0eab240 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -774,6 +774,7 @@ function valid_email_address($mail) {
 }
 
 /**
+ *
  * Verifies the syntax of the given URL.
  *
  * This function should only be used on actual URLs. It should not be used for
@@ -788,6 +789,8 @@ function valid_email_address($mail) {
  *   TRUE if the URL is in a valid format.
  *
  * @see \Drupal\Component\Utility\UrlValidator::isValid()
+ *
+ * @deprecated as of Drupal 8.0. Use UrlValidator::isValid() instead.
  */
 function valid_url($url, $absolute = FALSE) {
   return UrlValidator::isValid($url, $absolute);
@@ -5583,10 +5586,13 @@ function watchdog_severity_levels() {
 
 
 /**
+ *
  * Explodes a string of tags into an array.
  *
  * @see drupal_implode_tags()
  * @see \Drupal\Component\Utility\String::explodeTags().
+ *
+ * @deprecated as of Drupal 8.0. Use Tags::explode() instead.
  */
 function drupal_explode_tags($tags) {
   return Tags::explode($tags);
@@ -5597,6 +5603,8 @@ function drupal_explode_tags($tags) {
  *
  * @see drupal_explode_tags()
  * @see \Drupal\Component\Utility\String::implodeTags().
+ *
+ * @deprecated as of Drupal 8.0. Use Tags::implode() instead.
  */
 function drupal_implode_tags($tags) {
   return Tags::implode($tags);