Provide default value for email_change_date and don't allow it to be null

users/migrations/0088_auto_20200417_2312.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.28 on 2020-04-17 21:12
+from __future__ import unicode_literals
+
+import datetime
+from django.db import migrations, models
+from django.utils.timezone import utc
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0087_request_email'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='user',
+            name='email_change_date',
+            field=models.DateTimeField(auto_now_add=True, default=datetime.datetime(2020, 4, 17, 21, 12, 19, 739799, tzinfo=utc)),
+            preserve_default=False,
+        ),
+    ]

users/models.py

@@ -238,7 +238,7 @@ class User(
     shortcuts_enabled = models.BooleanField(
         verbose_name=_("enable shortcuts on Re2o website"), default=True
     )
-    email_change_date = models.DateTimeField(default=None, null=True)
+    email_change_date = models.DateTimeField(auto_now_add=True)
 
     USERNAME_FIELD = "pseudo"
     REQUIRED_FIELDS = ["surname", "email"]