diff --git a/src/Result/Item/Participant.php b/src/Result/Item/Participant.php
index 6d87f1f..dcaf49e 100644
--- a/src/Result/Item/Participant.php
+++ b/src/Result/Item/Participant.php
@@ -216,7 +216,7 @@ class Participant extends BaseItem
                     break;
                 }
 
-                $this->validFrom = Date::getDateTime($value, false, 'Y-m-d H:i:s');
+                $this->validFrom = Date::getDateTime($value, true);
                 break;
 
             case 'validuntil':
@@ -224,7 +224,7 @@ class Participant extends BaseItem
                     break;
                 }
 
-                $this->validUntil = Date::getDateTime($value, false, 'Y-m-d H:i:s');
+                $this->validUntil = Date::getDateTime($value, true);
                 break;
         }
     }
diff --git a/src/Result/Item/Survey.php b/src/Result/Item/Survey.php
index 0f83073..f793545 100644
--- a/src/Result/Item/Survey.php
+++ b/src/Result/Item/Survey.php
@@ -74,7 +74,7 @@ class Survey extends BaseItem
                     break;
                 }
 
-                $this->startsAt = Date::getDateTime($value, false, 'Y-m-d H:i:s');
+                $this->startsAt = Date::getDateTime($value, true);
                 break;
 
             case 'expires':
@@ -82,7 +82,7 @@ class Survey extends BaseItem
                     break;
                 }
 
-                $this->expiresAt = Date::getDateTime($value, false, 'Y-m-d H:i:s');
+                $this->expiresAt = Date::getDateTime($value, true);
                 break;
 
             case 'active':