diff --git a/bob/extension/test_utils.py b/bob/extension/test_utils.py
index 06247b0b7402a439906c09ca63a982495f51347f..77af867df9eeb90b645a0b78735797e27e5499b5 100644
--- a/bob/extension/test_utils.py
+++ b/bob/extension/test_utils.py
@@ -196,7 +196,7 @@ package-z
     result = link_documentation(additional_packages, stringio(f))
     expected = [
         'https://docs.python.org/%d.%d/' % sys.version_info[:2],
-        'https://matplotlib.org/',
+        'https://matplotlib.org/stable/',
         'https://setuptools.readthedocs.io/en/latest/',
         server % 'bob.extension',
         server % 'gridtk',
diff --git a/bob/extension/utils.py b/bob/extension/utils.py
index 56ebad9a2868a6175aa4f24fa8bb5f405182e21f..5b53f7a2ad1640ee36a2ab29cd0a81d6220e3c70 100644
--- a/bob/extension/utils.py
+++ b/bob/extension/utils.py
@@ -524,7 +524,7 @@ def link_documentation(additional_packages = ['python', 'numpy'], requirements_f
   _add_index('python', 'https://docs.python.org/%d.%d/' % sys.version_info[:2])
   _add_numpy_index()
   _add_index('scipy', 'https://docs.scipy.org/doc/scipy/')
-  _add_index('matplotlib', 'https://matplotlib.org/')
+  _add_index('matplotlib', 'https://matplotlib.org/stable/')
   _add_index('setuptools', 'https://setuptools.readthedocs.io/en/latest/')
   _add_index('six', 'https://six.readthedocs.io')
   _add_index('sqlalchemy', 'https://docs.sqlalchemy.org/en/latest/')