diff --git a/appveyor.yml b/appveyor.yml
index b9d354b..4062d10 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -27,6 +27,7 @@
 install:
   # Upgrade to the latest pip.
   - '%PYTHON%\\python.exe -m pip install -U pip setuptools wheel'
+  - '%PYTHON%\\python.exe -m pip install -r requirements_dev.txt'
   # Install win32api dependency. Must use the --only-binary switch explicitly
   # on AppVeyor
   - "%PYTHON%\\python.exe -m pip install --only-binary pywin32 pywin32"
diff --git a/requirements_dev.txt b/requirements_dev.txt
index a87eb7e..13f0c4e 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,11 +3,11 @@
 flake8==3.7.7
 mock==3.0.5
 pip==19.1.1
-pytest==4.5.0
+pytest==4.5.0 # pyup: <5.0 # for Python 2.7 support
 pytest-runner==5.1
 six==1.12.0
 Sphinx==1.8.5 # pyup: <2.0 # for Python 2.7 and 3.4 support
-tox==3.12.1
+tox==3.13.1
 twine==1.13.0
 watchdog==0.9.0
 wheel==0.33.4