diff --git a/docs/source/development/cronjob.rst b/docs/source/development/cronjob.rst
index df72fa922..bda32b5c8 100644
--- a/docs/source/development/cronjob.rst
+++ b/docs/source/development/cronjob.rst
@@ -39,9 +39,12 @@ Implements a :code:`Chill\MainBundle\Cron\CronJobInterface`. Here is an example:
     use Chill\MainBundle\Entity\CronJobExecution;
     use DateInterval;
     use DateTimeImmutable;
+    use Symfony\Component\Clock\ClockInterface;
 
     class MyCronJob implements CronJobInterface
     {
+        function __construct(private ClockInterface $clock) {}
+
         public function canRun(?CronJobExecution $cronJobExecution): bool
         {
             // the parameter $cronJobExecution contains data about the last execution of the cronjob
@@ -56,7 +59,7 @@ Implements a :code:`Chill\MainBundle\Cron\CronJobInterface`. Here is an example:
 
             // this cron job should be executed if the last execution is greater than one day, but only during the night
 
-            $now = new DateTimeImmutable('now');
+            $now = $clock->now();
 
             return $cronJobExecution->getLastStart() < $now->sub(new DateInterval('P1D'))
                 && in_array($now->format('H'), self::ACCEPTED_HOURS, true)
@@ -69,10 +72,15 @@ Implements a :code:`Chill\MainBundle\Cron\CronJobInterface`. Here is an example:
             return 'arbitrary-and-unique-key';
         }
 
-        public function run(): void
+        public function run(array $lastExecutionData): void
         {
             // here, we execute the command
-        }
+
+            // we return execution data, which will be served for next execution
+            // this data should be easily serializable in a json column: it should contains
+            // only int, string, etc. Avoid storing object
+            return ['last-execution-id' => 0];
+       }
     }
 
 How are cron job scheduled ?
diff --git a/src/Bundle/ChillMainBundle/Cron/CronJobInterface.php b/src/Bundle/ChillMainBundle/Cron/CronJobInterface.php
index 050b777e9..9194e6c53 100644
--- a/src/Bundle/ChillMainBundle/Cron/CronJobInterface.php
+++ b/src/Bundle/ChillMainBundle/Cron/CronJobInterface.php
@@ -24,9 +24,8 @@ interface CronJobInterface
      *
      * If data is returned, this data is passed as argument on the next execution
      *
-     * @param array $lastExecutionData the data which was returned from the previous execution
-     *
-     * @return array|null optionally return an array with the same data than the previous execution
+     * @param array<string|int, int|float|string|bool|array<int|string, int|float|string|bool>> $lastExecutionData the data which was returned from the previous execution
+     * @return array<string|int, int|float|string|bool|array<int|string, int|float|string|bool>>|null optionally return an array with the same data than the previous execution
      */
     public function run(array $lastExecutionData): ?array;
 }