diff --git a/Localization/ISO8601EnumArray.php b/Localization/ISO8601EnumArray.php
index e8e5bc794..b94809b3b 100644
--- a/Localization/ISO8601EnumArray.php
+++ b/Localization/ISO8601EnumArray.php
@@ -29,7 +29,7 @@ use phpOMS\Stdlib\Base\EnumArray;
  */
 class ISO8601EnumArray extends EnumArray
 {
-    protected static $constants = [
+    protected static array $constants = [
         1 => 'YYYY-MM-DD hh:mm:ss', // ietf: rfc3339
         2 => 'YYYY.MM.DD hh:mm:ss',
         3 => 'DD-MM-YYYY hh:mm:ss',
diff --git a/Localization/TimeZoneEnumArray.php b/Localization/TimeZoneEnumArray.php
index 59d34685b..5cfdd5825 100644
--- a/Localization/TimeZoneEnumArray.php
+++ b/Localization/TimeZoneEnumArray.php
@@ -26,7 +26,7 @@ use phpOMS\Stdlib\Base\EnumArray;
  */
 class TimeZoneEnumArray extends EnumArray
 {
-    protected static $constants = [
+    protected static array $constants = [
         0   => 'Africa/Abidjan',
         1   => 'Africa/Accra',
         2   => 'Africa/Addis_Ababa',
diff --git a/tests/Stdlib/Base/EnumArrayDemo.php b/tests/Stdlib/Base/EnumArrayDemo.php
index f39e344b5..25524d0cd 100644
--- a/tests/Stdlib/Base/EnumArrayDemo.php
+++ b/tests/Stdlib/Base/EnumArrayDemo.php
@@ -18,7 +18,7 @@ use phpOMS\Stdlib\Base\EnumArray;
 
 final class EnumArrayDemo extends EnumArray
 {
-    protected static $constants = [
+    protected static array $constants = [
         'ENUM1' => 1,
         'ENUM2' => 'abc',
     ];