diff --git a/scos_actions/calibration/sensor_calibration.py b/scos_actions/calibration/sensor_calibration.py
index 90f32b7c..d8bcd16f 100644
--- a/scos_actions/calibration/sensor_calibration.py
+++ b/scos_actions/calibration/sensor_calibration.py
@@ -7,7 +7,7 @@
 
 from scos_actions.calibration.interfaces.calibration import Calibration
 from scos_actions.calibration.utils import CalibrationEntryMissingException
-from scos_actions.utils import parse_datetime_iso_format_str
+from scos_actions.utils import parse_datetime_iso_format_str, get_datetime_str_now
 
 logger = logging.getLogger(__name__)
 
@@ -100,7 +100,7 @@ def expired(self) -> bool:
         env = Env()
         time_limit = env.int("CALIBRATION_EXPIRATION_LIMIT", default=None)
         logger.debug("Checking if calibration has expired.")
-        now_string = datetime.utcnow().isoformat(timespec="milliseconds") + "Z"
+        now_string = get_datetime_str_now()
         now = parse_datetime_iso_format_str(now_string)
         if time_limit is None:
             return False