diff --git a/devel.info.yml b/devel.info.yml
index a4df632..3571ca3 100644
--- a/devel.info.yml
+++ b/devel.info.yml
@@ -2,7 +2,7 @@ type: module
 name: Devel
 description: 'Various blocks, pages, and functions for developers.'
 package: Development
-core: 8.5
+core: 8.x
 configure: devel.admin_settings
 tags:
  - developer
diff --git a/devel.module b/devel.module
index 08b93e2..29776bd 100644
--- a/devel.module
+++ b/devel.module
@@ -20,6 +20,7 @@ use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Logger\RfcLogLevel;
 use Drupal\Core\Menu\LocalTaskDefault;
+use Drupal\Core\Messenger\MessengerInterface;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Url;
@@ -148,7 +149,7 @@ function devel_set_message($msg, $type = NULL) {
     drush_log($msg, $type);
   }
   else {
-    drupal_set_message($msg, $type, TRUE);
+    \Drupal::messenger()->addMessage($msg, $type, TRUE);
   }
 }
 
@@ -262,7 +263,7 @@ function backtrace_error_handler($error_level, $message, $filename, $line, $cont
     if (\Drupal::config('system.logging')->get('error_level') != 'hide') {
       $error_handlers = devel_get_handlers();
       if (!empty($error_handlers[DEVEL_ERROR_HANDLER_STANDARD])) {
-        drupal_set_message($msg, ($severity_level <= RfcLogLevel::NOTICE ? 'error' : 'warning'), TRUE);
+        \Drupal::messenger()->addMessage($msg, ($severity_level <= RfcLogLevel::NOTICE ? MessengerInterface::TYPE_ERROR : MessengerInterface::TYPE_WARNING), TRUE);
       }
       if (!empty($error_handlers[DEVEL_ERROR_HANDLER_BACKTRACE_KINT])) {
         print kpr(ddebug_backtrace(TRUE, 1), TRUE, $msg);
@@ -336,21 +337,21 @@ if (!function_exists('dd')) {
  *
  * Prints a variable to the 'message' area of the page.
  *
- * Uses drupal_set_message().
+ * Uses Drupal\Core\Messenger\MessengerInterface::addMessage()
  *
  * @param $input
  *   An arbitrary value to output.
  * @param string $name
  *   Optional name for identifying the output.
  * @param string $type
- *   Optional message type for drupal_set_message(), defaults to 'status'.
+ *   Optional message type see MessengerInterface, defaults to TYPE_STATUS.
  *
  * @return input
  *   The unaltered input value.
  *
  * @see \Drupal\devel\DevelDumperManager::message()
  */
-function dpm($input, $name = NULL, $type = 'status') {
+function dpm($input, $name = NULL, $type = MessengerInterface::TYPE_STATUS) {
   \Drupal::service('devel.dumper')->message($input, $name, $type);
   return $input;
 }
@@ -360,7 +361,7 @@ function dpm($input, $name = NULL, $type = 'status') {
  *
  * Displays a Variable::export() variable to the 'message' area of the page.
  *
- * Uses drupal_set_message().
+ * Uses Drupal\Core\Messenger\MessengerInterface::addMessage()
  *
  * @param $input
  *   An arbitrary value to output.
@@ -373,7 +374,7 @@ function dpm($input, $name = NULL, $type = 'status') {
  * @see \Drupal\devel\DevelDumperManager::message()
  */
 function dvm($input, $name = NULL) {
-  \Drupal::service('devel.dumper')->message($input, $name, 'status', 'drupal_variable');
+  \Drupal::service('devel.dumper')->message($input, $name, MessengerInterface::TYPE_STATUS, 'drupal_variable');
   return $input;
 }
 
diff --git a/devel_generate/devel_generate.info.yml b/devel_generate/devel_generate.info.yml
index 7b4e6ca..2304bab 100644
--- a/devel_generate/devel_generate.info.yml
+++ b/devel_generate/devel_generate.info.yml
@@ -2,6 +2,6 @@ type: module
 name: 'Devel generate'
 description: 'Generate dummy users, nodes, menus, taxonomy terms...'
 package: Development
-core: 8.5
+core: 8.x
 tags:
  - developer
diff --git a/kint/kint.module b/kint/kint.module
index c8bef22..53d7c5d 100644
--- a/kint/kint.module
+++ b/kint/kint.module
@@ -53,7 +53,7 @@ function ksm() {
   if (\Drupal::currentUser()->hasPermission('access kint')) {
     $args = func_get_args();
     $msg = @Kint::dump($args);
-    drupal_set_message(Markup::create($msg));
+    \Drupal::messenger()->addMessage(Markup::create($msg));
   }
 }
 
diff --git a/webprofiler/webprofiler.info.yml b/webprofiler/webprofiler.info.yml
index 1281184..0a1348f 100644
--- a/webprofiler/webprofiler.info.yml
+++ b/webprofiler/webprofiler.info.yml
@@ -2,7 +2,7 @@ name: Web Profiler
 type: module
 description: 'Drupal Web Profiler.'
 package: Development
-core: 8.5
+core: 8.x
 configure: webprofiler.settings
 tags:
  - developer