diff --git a/src/Collect/Support/Arr.php b/src/Collect/Support/Arr.php
index 47ef399..55059be 100644
--- a/src/Collect/Support/Arr.php
+++ b/src/Collect/Support/Arr.php
@@ -2,6 +2,7 @@
 
 namespace Tightenco\Collect\Support;
 
+use ArgumentCountError;
 use ArrayAccess;
 use Tightenco\Collect\Support\Traits\Macroable;
 use InvalidArgumentException;
@@ -458,7 +459,7 @@ public static function join($array, $glue, $finalGlue = '')
      * Key an associative array by a field or using a callback.
      *
      * @param  array  $array
-     * @param  callable|array|string
+     * @param  callable|array|string  $keyBy
      * @return array
      */
     public static function keyBy($array, $keyBy)
@@ -555,7 +556,11 @@ public static function map(array $array, callable $callback)
     {
         $keys = array_keys($array);
 
-        $items = array_map($callback, $array, $keys);
+        try {
+            $items = array_map($callback, $array, $keys);
+        } catch (ArgumentCountError) {
+            $items = array_map($callback, $array);
+        }
 
         return array_combine($keys, $items);
     }
diff --git a/src/Collect/Support/Collection.php b/src/Collect/Support/Collection.php
index f4bc2de..40b612a 100644
--- a/src/Collect/Support/Collection.php
+++ b/src/Collect/Support/Collection.php
@@ -1321,7 +1321,7 @@ public function sortDesc($options = SORT_REGULAR)
     /**
      * Sort the collection using the given callback.
      *
-     * @param  array<array-key, (callable(TValue, TKey): mixed)|array<array-key, string>|(callable(TValue, TKey): mixed)|string  $callback
+     * @param  array<array-key, (callable(TValue, TKey): mixed)|string|array{string, string}>|(callable(TValue, TKey): mixed)|string  $callback
      * @param  int  $options
      * @param  bool  $descending
      * @return static
@@ -1359,7 +1359,7 @@ public function sortBy($callback, $options = SORT_REGULAR, $descending = false)
     /**
      * Sort the collection using multiple comparisons.
      *
-     * @param  array<array-key, (callable(TValue, TKey): mixed)|array<array-key, string>  $comparisons
+     * @param  array<array-key, (callable(TValue, TKey): mixed)|string|array{string, string}>  $comparisons
      * @return static
      */
     protected function sortByMany(array $comparisons = [])
@@ -1401,7 +1401,7 @@ protected function sortByMany(array $comparisons = [])
     /**
      * Sort the collection in descending order using the given callback.
      *
-     * @param  array<array-key, (callable(TValue, TKey): mixed)|array<array-key, string>|(callable(TValue, TKey): mixed)|string  $callback
+     * @param  array<array-key, (callable(TValue, TKey): mixed)|string|array{string, string}>|(callable(TValue, TKey): mixed)|string  $callback
      * @param  int  $options
      * @return static
      */
diff --git a/src/Collect/Support/Traits/EnumeratesValues.php b/src/Collect/Support/Traits/EnumeratesValues.php
index e6d38b4..3104500 100644
--- a/src/Collect/Support/Traits/EnumeratesValues.php
+++ b/src/Collect/Support/Traits/EnumeratesValues.php
@@ -15,6 +15,7 @@
 use Symfony\Component\VarDumper\VarDumper;
 use Traversable;
 use UnexpectedValueException;
+use UnitEnum;
 
 /**
  * @template TKey of array-key
@@ -1005,6 +1006,8 @@ protected function getArrayableItems($items)
             return (array) $items->jsonSerialize();
         } elseif ($items instanceof Traversable) {
             return iterator_to_array($items);
+        } elseif ($items instanceof UnitEnum) {
+            return [$items];
         }
 
         return (array) $items;
diff --git a/tests/Support/Enums.php b/tests/Support/Enums.php
new file mode 100644
index 0000000..601b3ac
--- /dev/null
+++ b/tests/Support/Enums.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Tightenco\Collect\Tests\Support;
+
+enum TestEnum
+{
+    case A;
+}
+
+enum TestBackedEnum: int
+{
+    case A = 1;
+}
diff --git a/tests/Support/SupportArrTest.php b/tests/Support/SupportArrTest.php
index 5ad1fa4..a67b30d 100644
--- a/tests/Support/SupportArrTest.php
+++ b/tests/Support/SupportArrTest.php
@@ -632,6 +632,15 @@ public function testMap()
         $this->assertEquals(['first' => 'taylor', 'last' => 'otwell'], $data);
     }
 
+    public function testMapByReference()
+    {
+        $data = ['first' => 'taylor', 'last' => 'otwell'];
+        $mapped = Arr::map($data, 'strrev');
+
+        $this->assertEquals(['first' => 'rolyat', 'last' => 'llewto'], $mapped);
+        $this->assertEquals(['first' => 'taylor', 'last' => 'otwell'], $data);
+    }
+
     public function testPrepend()
     {
         $array = Arr::prepend(['one', 'two', 'three', 'four'], 'zero');
diff --git a/tests/Support/SupportCollectionTest.php b/tests/Support/SupportCollectionTest.php
index 9eb16a2..ddcc24e 100644
--- a/tests/Support/SupportCollectionTest.php
+++ b/tests/Support/SupportCollectionTest.php
@@ -24,6 +24,10 @@
 use Symfony\Component\VarDumper\VarDumper;
 use UnexpectedValueException;
 
+if (PHP_VERSION_ID >= 80100) {
+    include_once 'Enums.php';
+}
+
 class SupportCollectionTest extends TestCase
 {
     /**
@@ -4333,6 +4337,26 @@ public function testCollectionFromTraversableWithKeys($collection)
         $this->assertEquals(['foo' => 1, 'bar' => 2, 'baz' => 3], $data->toArray());
     }
 
+    /**
+     * @dataProvider collectionClassProvider
+     * @requires PHP >= 8.1
+     */
+    public function testCollectionFromEnum($collection)
+    {
+        $data = new $collection(TestEnum::A);
+        $this->assertEquals([TestEnum::A], $data->toArray());
+    }
+
+    /**
+     * @dataProvider collectionClassProvider
+     * @requires PHP >= 8.1
+     */
+    public function testCollectionFromBackedEnum($collection)
+    {
+        $data = new $collection(TestBackedEnum::A);
+        $this->assertEquals([TestBackedEnum::A], $data->toArray());
+    }
+
     /**
      * @dataProvider collectionClassProvider
      */
diff --git a/upgrade.sh b/upgrade.sh
index 7e30cf5..5a66179 100755
--- a/upgrade.sh
+++ b/upgrade.sh
@@ -147,6 +147,7 @@ carriageReturn="
     )
 
     tests=(
+        'Support/Enums.php'
         'Support/SupportCollectionTest.php'
         'Support/SupportArrTest.php'
         'Support/SupportMacroableTest.php'
@@ -380,7 +381,7 @@ function getCurrentVersionFromGitHub()
     echo Getting current version from $repository...
 
     if [ -z "$requestedVersion" ]; then
-        collectionVersion=$(git ls-remote $repository --tags  v9.17\* | grep tags/ | grep -v {} | cut -d \/ -f 3 | cut -d v -f 2  | grep -v RC | grep -vi beta | sort -t. -k 1,1n -k 2,2n -k 3,3n| tail -1)
+        collectionVersion=$(git ls-remote $repository --tags  v9.18\* | grep tags/ | grep -v {} | cut -d \/ -f 3 | cut -d v -f 2  | grep -v RC | grep -vi beta | sort -t. -k 1,1n -k 2,2n -k 3,3n| tail -1)
     else
         collectionVersion=$requestedVersion
     fi