diff --git a/doc/source/conf.py b/doc/source/conf.py
index <HASH>..<HASH> 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -84,7 +84,7 @@ extensions = [
     'sphinx.ext.autosummary',
     'sphinx.ext.autodoc',
     'sphinx.ext.viewcode',
-    'sphinx.ext.pngmath',
+    'sphinx.ext.imgmath',
     'numpydoc'
 ]
MAINT: replace deprecated pngmath extension by imgmath