diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 137edaf..86a62a9 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -29,7 +29,7 @@ jobs:
       fail-fast: true
       matrix:
         os: [ubuntu-latest]
-        php: [8.2, 8.3, 8.4]
+        php: [8.3, 8.4]
         stability: [prefer-lowest, prefer-stable]
 
     name: P${{ matrix.php }} - ${{ matrix.stability }} - ${{ matrix.os }}
@@ -59,7 +59,7 @@ jobs:
       fail-fast: true
       matrix:
         os: [windows-latest, macos-latest]
-        php: [8.2, 8.3, 8.4]
+        php: [8.3, 8.4]
         stability: [prefer-lowest, prefer-stable]
 
     name: P${{ matrix.php }} - ${{ matrix.stability }} - ${{ matrix.os }}
diff --git a/composer.json b/composer.json
index 4f1dd0d..1a716ef 100644
--- a/composer.json
+++ b/composer.json
@@ -3,7 +3,7 @@
     "description": "Universally Unique Lexicographically Sortable Identifier(ULID) for Laravel",
     "type": "library",
     "require": {
-        "php": "^8.2",
+        "php": "^8.3",
         "lewiscowles/ulid": "^1.3.1",
         "illuminate/support": "^11.30",
         "php-static-analysis/attributes": "^0.3.1",
diff --git a/src/Formatter/UlidFormatter.php b/src/Formatter/UlidFormatter.php
index 0fa6c02..0b7599a 100644
--- a/src/Formatter/UlidFormatter.php
+++ b/src/Formatter/UlidFormatter.php
@@ -4,9 +4,9 @@
 
 class UlidFormatter
 {
-    public const OPTION_LOWERCASE = 'lowercase';
+    public const string OPTION_LOWERCASE = 'lowercase';
 
-    public const OPTION_UPPERCASE = 'uppercase';
+    public const string OPTION_UPPERCASE = 'uppercase';
 
     protected $customFormatter;