diff --git a/custom_components/telenet_telemeter/manifest.json b/custom_components/telenet_telemeter/manifest.json
index 4b41dc6..fe2e6c0 100644
--- a/custom_components/telenet_telemeter/manifest.json
+++ b/custom_components/telenet_telemeter/manifest.json
@@ -9,5 +9,5 @@
     "iot_class": "cloud_polling",
     "issue_tracker": "https://github.com/myTselection/telenet_telemeter/issues",
     "requirements": ["beautifulsoup4", "html5lib"],
-    "version": "1.5.2"
+    "version": "1.5.3"
 }
\ No newline at end of file
diff --git a/custom_components/telenet_telemeter/sensor.py b/custom_components/telenet_telemeter/sensor.py
index 7c03cd9..380e4b0 100644
--- a/custom_components/telenet_telemeter/sensor.py
+++ b/custom_components/telenet_telemeter/sensor.py
@@ -773,15 +773,14 @@ async def async_update(self):
             self._last_update =  productdetails.get('lastupdated')
             self._product = productdetails.get('label')
             self._period_end_date = productdetails.get('nextbillingdate')
-            format_string = "%d-%m-%Y %H:%M:%S"
             # Parse the timestamp string into a datetime object
-            original_datetime = datetime.strptime(self._period_end_date, format_string)
+            original_datetime = datetime.strptime(self._period_end_date, _TELENET_DATETIME_FORMAT)
 
             # Add one day to the datetime object
             new_datetime = original_datetime + timedelta(days=1)
 
             # Format the new datetime object back to a string
-            self._period_end_date = new_datetime.strftime(format_string)
+            self._period_end_date = new_datetime.strftime(_TELENET_DATETIME_FORMAT)
             # get shared sensor
             sharedusage = productdetails.get('sharedusage')
             
@@ -914,15 +913,14 @@ async def async_update(self):
         self._last_update =  productdetails.get('lastupdated')
         self._product = productdetails.get('label')
         self._period_end_date = productdetails.get('nextbillingdate')
-        format_string = "%d-%m-%Y %H:%M:%S"
         # Parse the timestamp string into a datetime object
-        original_datetime = datetime.strptime(self._period_end_date, format_string)
+        original_datetime = datetime.strptime(self._period_end_date, _TELENET_DATETIME_FORMAT)
 
         # Add one day to the datetime object
         new_datetime = original_datetime + timedelta(days=1)
 
         # Format the new datetime object back to a string
-        self._period_end_date = new_datetime.strftime(format_string)
+        self._period_end_date = new_datetime.strftime(_TELENET_DATETIME_FORMAT)
         # get shared sensor
         unassignesub = productdetails.get('unassigned').get('mobilesubscriptions')[self._subsid]
         
@@ -1069,15 +1067,14 @@ async def async_update(self):
         self._last_update =  productdetails.get('lastupdated')
         self._product = productdetails.get('label')
         self._period_end_date = productdetails.get('nextbillingdate')
-        format_string = "%d-%m-%Y %H:%M:%S"
         # Parse the timestamp string into a datetime object
-        original_datetime = datetime.strptime(self._period_end_date, format_string)
+        original_datetime = datetime.strptime(self._period_end_date, _TELENET_DATETIME_FORMAT)
 
         # Add one day to the datetime object
         new_datetime = original_datetime + timedelta(days=1)
 
         # Format the new datetime object back to a string
-        self._period_end_date = new_datetime.strftime(format_string)
+        self._period_end_date = new_datetime.strftime(_TELENET_DATETIME_FORMAT)
         # get shared sensor
         profile = productdetails.get('profiles')[self._profileid]
         
@@ -1243,15 +1240,14 @@ async def async_update(self):
         self._last_update =  mobileusage.get('lastUpdated')
         self._label = self._product = self._productSubscription.get('label')
         self._period_end_date = mobileusage.get('nextBillingDate')
-        format_string = "%d-%m-%Y %H:%M:%S"
         # Parse the timestamp string into a datetime object
-        original_datetime = datetime.strptime(self._period_end_date, format_string)
+        original_datetime = datetime.strptime(self._period_end_date, _TELENET_DATETIME_FORMAT)
 
         # Add one day to the datetime object
         new_datetime = original_datetime + timedelta(days=1)
 
         # Format the new datetime object back to a string
-        self._period_end_date = new_datetime.strftime(format_string)
+        self._period_end_date = new_datetime.strftime(_TELENET_DATETIME_FORMAT)
         self._outofbundle = f"{mobileusage.get('outOfBundle').get('usedUnits')} {mobileusage.get('outOfBundle').get('unitType')}"
         self._number = self._identifier
         self._active = self._productSubscription.get('status')