diff --git a/environment.yml b/environment.yml
index 38cdc94b..20e0e0d6 100644
--- a/environment.yml
+++ b/environment.yml
@@ -8,7 +8,7 @@ dependencies:
   - pip:
     - jupyter-book
     - sphinx-multitoc-numbering
-    - quantecon-book-theme
+    - quantecon-book-theme==0.1.7
     - sphinx-tojupyter
     - sphinxext-rediraffe
     - sphinx-exercise