diff --git a/device/models.py b/device/models.py
index d7215af..8d38bf1 100644
--- a/device/models.py
+++ b/device/models.py
@@ -361,7 +361,7 @@ class Device:
     def updated(self):
         """get timestamp from last evidence created"""
         self.get_last_evidence()
-        return self.last_evidence.created
+        return self.last_evidence.get_time_created()
 
     @property
     def serial_number(self):
diff --git a/evidence/models.py b/evidence/models.py
index a056736..f7f3f52 100644
--- a/evidence/models.py
+++ b/evidence/models.py
@@ -135,9 +135,11 @@ class Evidence:
         if not self.doc:
             self.get_doc()
         self.created = self.doc.get("endTime")
-
         if not self.created:
-            self.created = self.properties.last().created
+            self.created = self.get_time_created()
+
+    def get_time_created(self):
+        return self.properties.last().created.isoformat()
 
     def get_components(self):
         if self.is_legacy():