diff --git a/setup.py b/setup.py
index a038021..90c9cb5 100644
--- a/setup.py
+++ b/setup.py
@@ -44,6 +44,7 @@ setup(name='plone.app.discussion',
           "Programming Language :: Python",
           "Programming Language :: Python :: 3.7",
           "Programming Language :: Python :: 3.8",
+          "Programming Language :: Python :: 3.9",
       ],
       keywords='plone discussion',
       author='Timo Stollenwerk - Plone Foundation',