diff --git a/requirements-dev.txt b/requirements-dev.txt
index 6f87f2fbc..04528c610 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -25,8 +25,7 @@ pytest-benchmark>=3.4.1
 pytest-cov>=3.0.0
 pytest-mock>=3.6.1
 teamcity-messages>=1.29
-tox>=3.27.1
-tox-factor>=0.1.2
+tox>=4.0.0
 
 # needed for building docs
 sphinx
diff --git a/testkit/Dockerfile b/testkit/Dockerfile
index b7a073208..623e63ffd 100644
--- a/testkit/Dockerfile
+++ b/testkit/Dockerfile
@@ -56,5 +56,5 @@ RUN pyenv global $(pyenv versions --bare --skip-aliases)
 RUN for version in $PYTHON_VERSIONS; do \
         python$version -m pip install -U pip && \
         python$version -m pip install -U setuptools && \
-        python$version -m pip install -U coverage tox tox-factor; \
+        python$version -m pip install -U coverage tox; \
     done