diff --git a/rector.php b/rector.php
index dd4380e3..2456d3ec 100644
--- a/rector.php
+++ b/rector.php
@@ -19,7 +19,6 @@
 
 use Rector\Config\RectorConfig;
 use Rector\Php70\Rector\FunctionLike\ExceptionHandlerTypehintRector;
-use Rector\Php71\Rector\FuncCall\CountOnNullRector;
 use Rector\PHPUnit\CodeQuality\Rector\Class_\AddSeeTestAnnotationRector;
 use Rector\PHPUnit\CodeQuality\Rector\Class_\PreferPHPUnitThisCallRector;
 use Rector\PHPUnit\Set\PHPUnitLevelSetList;
@@ -41,7 +40,6 @@
     $rectorConfig->importNames();
     $rectorConfig->importShortClasses(false);
     $rectorConfig->skip([
-        CountOnNullRector::class,
         ExceptionHandlerTypehintRector::class,
         AddSeeTestAnnotationRector::class,
         PreferPHPUnitThisCallRector::class,
diff --git a/src/DependencyInjection/SonataIntlExtension.php b/src/DependencyInjection/SonataIntlExtension.php
index 9e63200f..3eba5294 100644
--- a/src/DependencyInjection/SonataIntlExtension.php
+++ b/src/DependencyInjection/SonataIntlExtension.php
@@ -105,6 +105,8 @@ private function configureLocale(ContainerBuilder $container, array $config): vo
      * @param array<string> $timezones
      *
      * @throws \RuntimeException If one of the locales is invalid
+     *
+     * @phpstan-param array<non-empty-string> $timezones
      */
     private function validateTimezones(array $timezones): void
     {
diff --git a/src/Helper/DateTimeFormatter.php b/src/Helper/DateTimeFormatter.php
index 0c65d913..fecf93f1 100644
--- a/src/Helper/DateTimeFormatter.php
+++ b/src/Helper/DateTimeFormatter.php
@@ -135,9 +135,15 @@ public function getDatetime(
             }
         }
 
+        $timezone ??= $this->timezoneDetector->getTimezone();
+
+        if (null === $timezone || '' === $timezone) {
+            throw new \InvalidArgumentException('Invalid timezone provided');
+        }
+
         $date = new \DateTime();
         $date->setTimestamp($data);
-        $date->setTimezone(new \DateTimeZone($timezone ?? $this->timezoneDetector->getTimezone() ?? ''));
+        $date->setTimezone(new \DateTimeZone($timezone));
 
         return $date;
     }
diff --git a/src/Helper/DateTimeFormatterInterface.php b/src/Helper/DateTimeFormatterInterface.php
index 84c5fbda..682ceb67 100644
--- a/src/Helper/DateTimeFormatterInterface.php
+++ b/src/Helper/DateTimeFormatterInterface.php
@@ -24,6 +24,8 @@ interface DateTimeFormatterInterface
 {
     /**
      * @param int|null $dateType See \IntlDateFormatter::getDateType
+     *
+     * @phpstan-param non-empty-string|null $timezone
      */
     public function formatDate(
         \DateTimeInterface|string|int $date,
@@ -35,6 +37,8 @@ public function formatDate(
     /**
      * @param int|null $dateType See \IntlDateFormatter::getDateType
      * @param int|null $timeType See \IntlDateFormatter::getTimeType
+     *
+     * @phpstan-param non-empty-string|null $timezone
      */
     public function formatDateTime(
         \DateTimeInterface|string|int $datetime,
@@ -46,6 +50,8 @@ public function formatDateTime(
 
     /**
      * @param int|null $timeType See \IntlDateFormatter::getTimeType
+     *
+     * @phpstan-param non-empty-string|null $timezone
      */
     public function formatTime(
         \DateTimeInterface|string|int $time,
@@ -54,6 +60,9 @@ public function formatTime(
         ?int $timeType = null
     ): string;
 
+    /**
+     * @phpstan-param non-empty-string|null $timezone
+     */
     public function format(
         \DateTimeInterface|string|int $datetime,
         string $pattern,
@@ -63,6 +72,8 @@ public function format(
 
     /**
      * Gets a date time instance by a given data and timezone.
+     *
+     * @phpstan-param non-empty-string|null $timezone
      */
     public function getDatetime(
         \DateTimeInterface|string|int $data,
diff --git a/src/Twig/DateTimeRuntime.php b/src/Twig/DateTimeRuntime.php
index 2cd3ee76..159e8e29 100644
--- a/src/Twig/DateTimeRuntime.php
+++ b/src/Twig/DateTimeRuntime.php
@@ -22,6 +22,9 @@ public function __construct(private DateTimeFormatterInterface $helper)
     {
     }
 
+    /**
+     * @phpstan-param non-empty-string|null $timezone
+     */
     public function formatDate(
         \DateTimeInterface|string|int $date,
         ?string $pattern = null,
@@ -36,6 +39,9 @@ public function formatDate(
         return $this->helper->formatDate($date, $locale, $timezone, $dateType);
     }
 
+    /**
+     * @phpstan-param non-empty-string|null $timezone
+     */
     public function formatTime(
         \DateTimeInterface|string|int $time,
         ?string $pattern = null,
@@ -50,6 +56,9 @@ public function formatTime(
         return $this->helper->formatTime($time, $locale, $timezone, $timeType);
     }
 
+    /**
+     * @phpstan-param non-empty-string|null $timezone
+     */
     public function formatDatetime(
         \DateTimeInterface|string|int $time,
         ?string $pattern = null,