diff --git a/doc/source/contributor/tutorials/plugin.rst b/doc/source/contributor/tutorials/plugin.rst
index 280a19c73f..12dde77c90 100644
--- a/doc/source/contributor/tutorials/plugin.rst
+++ b/doc/source/contributor/tutorials/plugin.rst
@@ -294,6 +294,7 @@ setup.cfg
         License :: OSI Approved :: Apache Software License
         Operating System :: POSIX :: Linux
         Programming Language :: Python
+        Programming Language :: Python :: 3 :: Only
         Programming Language :: Python :: 3
         Programming Language :: Python :: 3.6
         Programming Language :: Python :: 3.7
diff --git a/setup.cfg b/setup.cfg
index bcdd5b606c..0c7a5578aa 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -17,6 +17,7 @@ classifier =
     Operating System :: OS Independent
     Operating System :: POSIX :: Linux
     Programming Language :: Python
+    Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7