diff --git a/README.md b/README.md
index c8e6e5d..46d5599 100644
--- a/README.md
+++ b/README.md
@@ -69,7 +69,7 @@ cleantoots clean --delete  # Delete without prompt.
 ```
 
 ## Tested environments
-Cleantoots test suite runs on latest versions of macOS, Windows and Ubuntu
-as GitHub Actions understands it. See
+Cleantoots test suite runs on Python 3.6, 3.7 and 3.8
+on latest versions of macOS, Windows and Ubuntu as GitHub Actions understands it. See
 (the docs)[https://help.github.com/en/actions/automating-your-workflow-with-github-actions/workflow-syntax-for-github-actions#jobsjob_idruns-on]
 for more information on what "latest" means".