diff --git a/.travis.yml b/.travis.yml
index e15070e..d56f24c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,11 @@
 language: rust
 rust:
+  # error on #[non_exhaustive] being "experimental"
+  # - 1.36.0
+  # - 1.37.0
+  # error on cfg(doctest)
+  # - 1.38.0
+  # - 1.39.0
   - 1.40.0
   - 1.41.0
   - 1.42.0