diff --git a/Dockerfile b/Dockerfile
index 2cdf8a3..992c3e7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,7 +8,7 @@ ENV PIPENV_VENV_IN_PROJECT yes
 COPY Pipfile Pipfile.lock feedmixer_api.py feedmixer_wsgi.py feedmixer.py /app/
 
 WORKDIR /app/
-RUN pipenv --three sync && apt purge
+RUN pipenv sync && apt purge
 RUN pipenv run pip3 install gunicorn
 
 # build layer without git:
diff --git a/README.rst b/README.rst
index 6378ca6..7cc6e9a 100644
--- a/README.rst
+++ b/README.rst
@@ -90,7 +90,7 @@ Installation
    ``$ git clone https://github.com/cristoper/feedmixer.git``
 #. ``$ cd feedmixer``
 #. Recommended: use pipenv_ to create a virtualenv and install dependencies:
-   ``$ pipenv --three sync``
+   ``$ pipenv sync``
 
 The project consists of three modules: