diff --git a/.travis.yml b/.travis.yml
index f918f54c..d380ee43 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,9 +21,10 @@ dist:
 
 # https://docs.travis-ci.com/user/reference/osx/#macos-version
 osx_image:
-- xcode9.4.1
-- xcode10.3
-- xcode11.3
+- xcode9.4.1  # macOS 10.13
+- xcode10.3   # macOS 10.14.4
+- xcode11.3   # macOS 10.14.6
+- xcode12u    # macOS 10.15.5
 
 env:
 - PYTHON_BUILD_VERSION=3.8.0