diff --git a/setup.py b/setup.py
index cf8626e87..5ef6378e7 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,7 @@ from version import VERSION
 # Environment-specific dependencies.
 extras = {
   'atari': ['atari_py>=0.1.1', 'Pillow', 'PyOpenGL'],
-  'box2d': ['box2d-py'],
+  'box2d': ['box2d-py>=2.3.4'],
   'classic_control': ['PyOpenGL'],
   'mujoco': ['mujoco_py>=1.50', 'imageio'],
   'robotics': ['mujoco_py>=1.50', 'imageio'],
diff --git a/tox.ini b/tox.ini
index 7563712f7..347b5f47b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,12 +16,3 @@ deps =
 commands =
     pytest {posargs}
 
-[testenv:py27]
-whitelist_externals=make
-passenv=DISPLAY TRAVIS*
-deps =
-    pytest
-    mock
-    -e .[all]
-commands =
-    pytest {posargs}