diff --git a/ietf/ietfauth/forms.py b/ietf/ietfauth/forms.py
index 141072a7f..fe56c7ca9 100644
--- a/ietf/ietfauth/forms.py
+++ b/ietf/ietfauth/forms.py
@@ -246,7 +246,7 @@ class ChangePasswordForm(forms.Form):
 
 
 class ChangeUsernameForm(forms.Form):
-    username = forms.ChoiceField(choices=['-','--------'])
+    username = forms.ChoiceField(choices=[('-','--------')])
     password = forms.CharField(widget=forms.PasswordInput, help_text="Confirm the change with your password")
 
     def __init__(self, user, *args, **kwargs):
diff --git a/ietf/ietfauth/views.py b/ietf/ietfauth/views.py
index 642e91339..11348e9be 100644
--- a/ietf/ietfauth/views.py
+++ b/ietf/ietfauth/views.py
@@ -50,8 +50,7 @@ from django.contrib.auth.hashers import identify_hasher
 from django.contrib.auth.models import User
 from django.contrib.auth.views import LoginView
 from django.contrib.sites.models import Site
-from django.core.exceptions import ObjectDoesNotExist
-from django.core.validators import ValidationError
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.urls import reverse as urlreverse
 from django.utils.safestring import mark_safe
 from django.http import Http404, HttpResponseRedirect  #, HttpResponse, 
diff --git a/ietf/liaisons/forms.py b/ietf/liaisons/forms.py
index 7ad5b2dd9..f72becd78 100644
--- a/ietf/liaisons/forms.py
+++ b/ietf/liaisons/forms.py
@@ -13,12 +13,12 @@ from form_utils.forms import BetterModelForm
 
 from django import forms
 from django.conf import settings
-from django.core.exceptions import ObjectDoesNotExist
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.db.models.query import QuerySet
 from django.forms.utils import ErrorList
 from django.db.models import Q
 #from django.forms.widgets import RadioFieldRenderer
-from django.core.validators import validate_email, ValidationError
+from django.core.validators import validate_email
 
 import debug                            # pyflakes:ignore
 
diff --git a/ietf/liaisons/views.py b/ietf/liaisons/views.py
index 78fc164dc..676a302e4 100644
--- a/ietf/liaisons/views.py
+++ b/ietf/liaisons/views.py
@@ -7,7 +7,8 @@ from email.utils import parseaddr
 
 from django.contrib import messages
 from django.urls import reverse as urlreverse
-from django.core.validators import validate_email, ValidationError
+from django.core.exceptions import ValidationError
+from django.core.validators import validate_email
 from django.db.models import Q, Prefetch
 from django.http import HttpResponse
 from django.shortcuts import render, get_object_or_404, redirect
diff --git a/ietf/submit/mail.py b/ietf/submit/mail.py
index 32dd89e25..93370990e 100644
--- a/ietf/submit/mail.py
+++ b/ietf/submit/mail.py
@@ -11,7 +11,7 @@ import pyzmail
 
 from django.conf import settings
 from django.urls import reverse as urlreverse
-from django.core.validators import ValidationError
+from django.core.exceptions import ValidationError
 from django.contrib.sites.models import Site
 from django.template.loader import render_to_string
 from django.utils.encoding import force_text, force_str
diff --git a/ietf/submit/utils.py b/ietf/submit/utils.py
index e75d3f323..5817a3fe5 100644
--- a/ietf/submit/utils.py
+++ b/ietf/submit/utils.py
@@ -12,7 +12,8 @@ import time
 from typing import Callable, Optional # pyflakes:ignore
 
 from django.conf import settings
-from django.core.validators import validate_email, ValidationError
+from django.core.exceptions import ValidationError
+from django.core.validators import validate_email 
 from django.db import transaction
 from django.http import HttpRequest     # pyflakes:ignore
 from django.utils.module_loading import import_string
diff --git a/ietf/submit/views.py b/ietf/submit/views.py
index d54db999a..51cb65a1f 100644
--- a/ietf/submit/views.py
+++ b/ietf/submit/views.py
@@ -13,7 +13,7 @@ from django.contrib import messages
 from django.contrib.auth.models import User
 from django.db import DataError
 from django.urls import reverse as urlreverse
-from django.core.validators import ValidationError
+from django.core.exceptions import ValidationError
 from django.http import HttpResponseRedirect, Http404, HttpResponseForbidden, HttpResponse
 from django.http import HttpRequest     # pyflakes:ignore
 from django.shortcuts import get_object_or_404, redirect, render
diff --git a/requirements.txt b/requirements.txt
index 1c23bb895..dacfb533e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -20,7 +20,7 @@ django-oidc-provider>=0.7
 django-password-strength>=1.2.1
 django-referrer-policy>=1.0
 django-simple-history>=2.3.0
-django-stubs==1.3.0		# The django-stubs version used determines the the mypy version indicated below
+django-stubs==1.6.0		# The django-stubs version used determines the the mypy version indicated below
 django-tastypie>=0.14.3         # Django 2.1 will require 0.14.2; Django 3.0 will require 0.14.3
 django-webtest>=1.9.7
 django-widget-tweaks>=1.4.2
@@ -38,7 +38,7 @@ logging_tree>=1.8.1
 lxml>=3.4.0,<5
 markdown2>=2.3.8
 mock>=2.0.0
-mypy==0.750			# Version requirements determined by django-stubs.
+mypy>=0.782,<0.790			# Version requirements determined by django-stubs.
 mysqlclient>=1.3.13
 oic>=1.2
 pathlib>=1.0