diff --git a/generic/views.py b/generic/views.py
index a0f04362..73ab0a07 100644
--- a/generic/views.py
+++ b/generic/views.py
@@ -320,7 +320,7 @@ class ExamViews(View, LoginRequiredMixin):
         for exam in exams:
             if exam.active:
                 if exam.json_creation_time:
-                    creation_time = exam.json_creation_time.timestamp()
+                    creation_time = exam.json_creation_time.isoformat()
                 else:
                     creation_time = "None"
                 active_exams["exams"].append(
@@ -378,15 +378,16 @@ class ExamViews(View, LoginRequiredMixin):
             return redirect(url)
             return JsonResponse(exam_json_cache)
 
+        time = datetime.now()
 
         with open(path, "w+") as f:
             exam_json = exam.get_exam_json()
-            exam_json["generated"] = datetime.now().timestamp()
+            exam_json["generated"] = time.isoformat()
             f.write(json.dumps(exam_json))
 
         exam.recreate_json = False
 
-        exam.json_creation_time = datetime.now()
+        exam.json_creation_time = time
         exam.save()
 
         # We also try to clear the cache of any associated questions (longs)
diff --git a/longs/models.py b/longs/models.py
index 3c13f76b..89e04481 100644
--- a/longs/models.py
+++ b/longs/models.py
@@ -120,7 +120,7 @@ class Long(models.Model):
         help_text="If the json cache needs updating", default=False
     )
 
-    json_creation_time = models.DateTimeField(blank=True, default=None, null=True)
+    json_creation_time = models.DateTimeField(blank=True, default=None)
 
     #question_file = models.FileField(upload_to=question_file_directory_path, blank=True, null=True)
 
@@ -182,7 +182,7 @@ class Long(models.Model):
             "title": "{}",
             "type": "long",
             "generated": "{}",
-            """.format(q.history, datetime.datetime.now().timestamp())
+            """.format(q.history, datetime.datetime.now().isoformat())
             )