diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80dd8afdbfb8776c8a579a843c87bde2b2be522e..28e5127a0666f37e95d51092c2be0f6d0b106190 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -119,6 +119,8 @@ API-breaking change is listed.
 - Rename `map_union_subseteq_l_alt` → `map_union_subseteq_l'` and
   `map_union_subseteq_r_alt` → `map_union_subseteq_r'` to be consistent with
   `or_intro_{l,r}'`.
+- Add `union_subseteq_l'`, `union_subseteq_r'` as versions of
+  `union_subseteq_l`, `union_subseteq_r` that can be more easily `apply`ed.
 
 The following `sed` script should perform most of the renaming
 (on macOS, replace `sed` by `gsed`, installed via e.g. `brew install gnu-sed`).