diff --git a/src/Form/DateRangeFormatForm.php b/src/Form/DateRangeFormatForm.php
index 948ce67..79aeb2f 100644
--- a/src/Form/DateRangeFormatForm.php
+++ b/src/Form/DateRangeFormatForm.php
@@ -207,13 +207,13 @@ class DateRangeFormatForm extends EntityForm {
 
     switch ($status) {
       case SAVED_NEW:
-        drupal_set_message($this->t('Created the %label date range format.', [
+        $this->messenger()->addMessage($this->t('Created the %label date range format.', [
           '%label' => $date_range_format->label(),
         ]));
         break;
 
       default:
-        drupal_set_message($this->t('Updated the %label date range format.', [
+        $this->messenger()->addMessage($this->t('Updated the %label date range format.', [
           '%label' => $date_range_format->label(),
         ]));
     }
diff --git a/src/Tests/DateRangeCompactFormatterTest.php b/src/Tests/DateRangeCompactFormatterTest.php
index a5e8e2b..cfc4545 100644
--- a/src/Tests/DateRangeCompactFormatterTest.php
+++ b/src/Tests/DateRangeCompactFormatterTest.php
@@ -2,7 +2,6 @@
 
 namespace Drupal\daterange_compact\Tests;
 
-use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
 use Drupal\Core\Entity\Entity\EntityViewDisplay;
 use Drupal\Core\Entity\FieldableEntityInterface;
@@ -81,8 +80,8 @@ class DateRangeCompactFormatterTest extends KernelTestBase {
 
     $this->entityType = 'entity_test';
     $this->bundle = $this->entityType;
-    $this->dateFieldName = Unicode::strtolower($this->randomMachineName());
-    $this->dateTimeFieldName = Unicode::strtolower($this->randomMachineName());
+    $this->dateFieldName = mb_strtolower($this->randomMachineName());
+    $this->dateTimeFieldName = mb_strtolower($this->randomMachineName());
 
     // Create a typical format for USA.
     $usa_format = DateRangeFormat::create([