diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 212c10a..7d6301a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php: [7.4, 8.0]
+        php: [7.4, 8.0, 8.1]
         deps: [hightest]
         symfony: [4.4.*, 5.3.*, 5.4.*]
         include:
@@ -22,6 +22,9 @@ jobs:
           - php: 8.0
             deps: hightest
             symfony: 6.0.*
+          - php: 8.1
+            deps: hightest
+            symfony: 6.0.*
     steps:
       - uses: zenstruck/.github@php-test-symfony
         with:
diff --git a/src/Schedule/Task/CompoundTask.php b/src/Schedule/Task/CompoundTask.php
index f7c927f..e917cbb 100644
--- a/src/Schedule/Task/CompoundTask.php
+++ b/src/Schedule/Task/CompoundTask.php
@@ -81,7 +81,7 @@ public function addMessage(object $message, array $stamps = [], ?string $descrip
     /**
      * @return Task[]
      */
-    public function getIterator(): iterable
+    public function getIterator(): \Traversable
     {
         foreach ($this->tasks as $task) {
             $task->cron($this->getExpression());