diff --git a/environment.yml b/environment.yml
index 26ef16c..e35df9d 100644
--- a/environment.yml
+++ b/environment.yml
@@ -9,7 +9,7 @@ dependencies:
     - jupyter-book==1.0.4post1
     - quantecon-book-theme==0.15.1
     - sphinx-tojupyter==0.6.0
-    - sphinx-proof==0.3.0
+    - sphinx-proof==0.4.0
     - sphinxext-rediraffe==0.3.0
     - sphinx-exercise==1.2.1
     - sphinxcontrib-youtube==1.4.1