diff --git a/.test-py3.yml b/.test-py3.yml
index c0919c3dd82cd73e510bc5d97776aa8699ad0a7a..bd1f2bd30934d60b3d9ac358a46815ccf8302960 100644
--- a/.test-py3.yml
+++ b/.test-py3.yml
@@ -6,7 +6,7 @@ channels:
 dependencies:
  - conda-forge::numpy
  - conda-forge::sympy
- - python=3.7
+ - python=3.6
  - symengine::python-symengine=0.3.0
 # - pexpect
 # - maxima