diff --git a/.travis.yml b/.travis.yml
index 8c86e55a..0256e44b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,9 @@ language: python
 dist: xenial
 cache: pip
 python:
-    - 3.7
+    # minimum required Python version
+    - 3.6
+    - 3.9
     - nightly
     - pypy3
 install: