diff --git a/requirements.txt b/requirements.txt
index 0071bc83..f4ece220 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,14 +4,14 @@ django-bootstrap-datepicker-plus~=3.0.5
 django-cas-server~=1.2.0
 django-colorfield~=0.3.2
 django-crispy-forms~=1.7.2
-django-extensions~=2.1.4
-django-filter~=2.1.0
+django-extensions>=2.1.4
+django-filter~=2.1
 django-htcpcp-tea~=0.3.1
 django-mailer~=2.0.1
 django-oauth-toolkit~=1.3.3
 django-phonenumber-field~=5.0.0
-django-polymorphic~=2.0.3
-djangorestframework~=3.9.0
+django-polymorphic>=2.0.3,<3.0.0
+djangorestframework>=3.9.0,<3.13.0
 django-rest-polymorphic~=0.1.9
 django-tables2~=2.3.1
 python-memcached~=1.59