diff --git a/Dockerfile b/Dockerfile
index e1406b4..74e9cfb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,4 +5,4 @@ LABEL Description="This image should provide environment to lint neotags" Vendor
 
 # Install dependencies
 RUN pip install --upgrade pip
-RUN pip install --no-cache-dir pep8 neovim pyfakefs
+RUN pip install --no-cache-dir pep8 neovim pyfakefs==3.1
diff --git a/readme.rst b/readme.rst
index 995af81..1afbfbc 100644
--- a/readme.rst
+++ b/readme.rst
@@ -44,7 +44,7 @@ Development
 
 Install dependencies:
 
-- ``pip install pyfakefs``
+- ``pip install pyfakefs==3.1``
 
 Run tests: