diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4c44b67..0a7d33c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
       fail-fast: false
       matrix:
         stability: [prefer-stable]
-        php: [8.1, 8.2]
+        php: [8.1, 8.2, 8.3, 8.4]
         laravel: [10]
 
     name: PHP ${{ matrix.php }} - Laravel ${{ matrix.laravel }}
diff --git a/composer.json b/composer.json
index c9740a3..ec0d71f 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,8 @@
     "api-ecosystem-for-laravel/dingo-api": "^4.1",
     "php-open-source-saver/jwt-auth": "^2.1",
     "illuminate/support": "^10.0",
-    "ramsey/uuid": "^4.3"
+    "ramsey/uuid": "^4.3",
+    "nesbot/carbon": "^2.0|^3.0"
   },
   "require-dev": {
     "ext-json": "*",
diff --git a/src/Transformers/RestfulTransformer.php b/src/Transformers/RestfulTransformer.php
index af7fc11..0879aa3 100644
--- a/src/Transformers/RestfulTransformer.php
+++ b/src/Transformers/RestfulTransformer.php
@@ -2,6 +2,8 @@
 
 namespace Specialtactics\L5Api\Transformers;
 
+use DateTimeInterface;
+use Carbon\Carbon;
 use League\Fractal\TransformerAbstract;
 use Specialtactics\L5Api\APIBoilerplate;
 use Specialtactics\L5Api\Models\RestfulModel;
@@ -9,6 +11,8 @@
 
 class RestfulTransformer extends TransformerAbstract
 {
+    public const DATE_CAST_TYPES = ['date', 'datetime', 'immutable_date', 'immutable_datetime'];
+
     /**
      * @var RestfulModel The model to be transformed
      */
@@ -82,11 +86,19 @@ public function transformRestfulModel(EloquentModel $model)
         }, ARRAY_FILTER_USE_KEY);
 
         /*
-         * Format all dates as Iso8601 strings, this includes the created_at and updated_at columns
+         * Format all dates as Iso8601 strings, this includes timestamped columns
          */
-        foreach ($model->getDates() as $dateColumn) {
+        foreach ($this->getModelDateFields($model) as $dateColumn) {
             if (! empty($model->$dateColumn) && ! in_array($dateColumn, $filterOutAttributes)) {
-                $transformed[$dateColumn] = $model->$dateColumn->toIso8601String();
+                if ($model->$dateColumn instanceof DateTimeInterface) {
+                    $transformed[$dateColumn] = Carbon::instance($model->$dateColumn)->toIso8601String();
+                } else {
+                    try {
+                        $transformed[$dateColumn] = Carbon::parse($model->$dateColumn)->toIso8601String();
+                    } catch (\Error $e) {
+                        $transformed[$dateColumn] = $model->$dateColumn;
+                    }
+                }
             }
         }
 
@@ -253,4 +265,26 @@ protected function transformRelations(array $transformed)
 
         return $transformed;
     }
+
+    protected function getModelDateFields(EloquentModel $model): array
+    {
+        $dateFields = [];
+
+        foreach ($model->getDates() as $dateColumn) {
+            $dateFields[] = $dateColumn;
+        }
+
+        // For previous versions of Eloquent, dates were stored as arrays
+        if ($model->dates && is_array($model->dates)) {
+            $dateFields = array_merge($model->dates, $dateFields);
+        }
+
+        foreach ($model->getCasts() as $field => $castType) {
+            if (in_array($castType, static::DATE_CAST_TYPES)) {
+                $dateFields[] = $field;
+            }
+        }
+
+        return array_unique($dateFields);
+    }
 }