diff --git a/docs/misc/changelog.rst b/docs/misc/changelog.rst
index 34aec66..9f5e600 100644
--- a/docs/misc/changelog.rst
+++ b/docs/misc/changelog.rst
@@ -3,7 +3,7 @@
 Changelog
 ==========
 
-Pre-Release 0.6.0a3 (WIP)
+Pre-Release 0.6.0a4 (WIP)
 ------------------------------
 
 
diff --git a/setup.py b/setup.py
index 2718daa..f07e89a 100644
--- a/setup.py
+++ b/setup.py
@@ -105,7 +105,7 @@ setup(name='stable_baselines3',
             # For render
             'opencv-python',
             # For atari games,
-            'gym[classic_control,atari]>=0.11'
+            'atari_py~=0.2.0', 'Pillow'
         ]
       },
       description='Pytorch version of Stable Baselines, implementations of reinforcement learning algorithms.',
diff --git a/stable_baselines3/version.txt b/stable_baselines3/version.txt
index 02e53e5..25c2e1d 100644
--- a/stable_baselines3/version.txt
+++ b/stable_baselines3/version.txt
@@ -1 +1 @@
-0.6.0a3
+0.6.0a4