diff --git a/README.md b/README.md
index dfadaab..66dc04e 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ Prediction is sampled after 110K iterations, and I only implemented one-step tra
 # Dependency
 * MacOS 10.12 or Ubuntu 16.04
 * PyTorch v0.4.0
-* Python 3.5 or 3.6 
+* Python 3.6, 3.5 or 2.7 (deprecated)
 * Core dependencies: `pip install -r requirements.txt`
 * Optional: [Roboschool](https://github.com/openai/roboschool), [DeepMind Control Suite](https://github.com/deepmind/dm_control)+[DMControl2Gym](dm_control2gym)
 
diff --git a/requirements.txt b/requirements.txt
index f5bd612..7a37e6d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,5 +7,6 @@ tensorboardX==1.1
 scikit-image>=0.13.1
 tqdm>=4.23.0
 pandas>=0.22.0
-pathlib>=1.0.1
+pathlib2>=1.0.1;python_version <= '2.7'
+pathlib>=1.0.1;python_version >= '3.5'
 seaborn>=0.8.1
\ No newline at end of file
diff --git a/utils/misc.py b/utils/misc.py
index 8065109..b07af58 100644
--- a/utils/misc.py
+++ b/utils/misc.py
@@ -9,8 +9,13 @@ import pickle
 import os
 import datetime
 import uuid
-import pathlib
 import torch
+try:
+    # python >= 3.5
+    from pathlib import Path
+except:
+    # python == 2.7
+    from pathlib2 import Path
 
 def run_episodes(agent):
     config = agent.config
@@ -83,7 +88,7 @@ def sync_grad(target_network, src_network):
         param._grad = src_param.grad.clone()
 
 def mkdir(path):
-    pathlib.Path(path).mkdir(parents=True, exist_ok=True)
+    Path(path).mkdir(parents=True, exist_ok=True)
 
 def set_one_thread():
     os.environ['OMP_NUM_THREADS'] = '1'