diff --git a/environment.yml b/environment.yml
index 48e0a6b3..a4e6c3ad 100644
--- a/environment.yml
+++ b/environment.yml
@@ -1,8 +1,10 @@
 name: py36
 channels:
   - conda-forge
+  - default
 dependencies:
-  - python==3.6
+  - python=3.6
+  - sphinx=1.5.3
   - sphinx_rtd_theme=0.2.4
   - pip
   - openssl