diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 433f026..0aecf95 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,8 +9,8 @@ py37-django22:
     - >
         apt-get update &&
         apt-get install --no-install-recommends -t buster-backports -y
-        python3-django python3-django-casclient python3-django-reversion python3-djangorestframework
-        python3-docutils python3-pil python3-tz python3-six python3-sqlparse python3-stdnum python3-yaml python3-coreapi tox
+        python3-django python3-django-reversion python3-djangorestframework
+        python3-docutils tox
   script: tox -e py37
 
 py38-django22:
@@ -22,8 +22,8 @@ py38-django22:
     - >
         apt-get update &&
         apt-get install --no-install-recommends -y
-        python3-django python3-django-casclient python3-django-reversion python3-djangorestframework
-        python3-docutils python3-pil python3-tz python3-six python3-sqlparse python3-stdnum python3-yaml python3-coreapi tox
+        python3-django python3-django-reversion python3-djangorestframework
+        python3-docutils tox
   script: tox -e py38
 
 py39-django22:
@@ -33,13 +33,13 @@ py39-django22:
     - >
         apt-get update &&
         apt-get install --no-install-recommends -y
-        python3-django python3-django-casclient python3-django-reversion python3-djangorestframework
-        python3-docutils python3-pil python3-tz python3-six python3-sqlparse python3-stdnum python3-yaml python3-coreapi tox
+        python3-django python3-django-reversion python3-djangorestframework
+        python3-docutils tox
   script: tox -e py39
 
 linters:
   stage: quality-assurance
-  image: debian:buster-backports
+  image: debian:bullseye
   before_script:
     - apt-get update && apt-get install -y tox
   script: tox -e linters
diff --git a/requirements.txt b/requirements.txt
index fb744fb..87e8fad 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,13 +1,6 @@
-Django~=2.2.10
-docutils~=0.14
-Pillow>=8.0.1
-pytz~=2020.4
-six~=1.15
-sqlparse~=0.3
+docutils~=0.16  # for Django-admin docs
+Django~=2.2
 django-filter~=2.4
 django-reversion~=3.0
-python-stdnum~=1.14
-djangorestframework~=3.12.1
-pyyaml~=5.3.1
-coreapi~=2.3.3
-django_extensions~=3.1
\ No newline at end of file
+djangorestframework~=3.12
+django_extensions~=3.0