diff --git a/README.md b/README.md
index c324932..262de03 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,8 @@ It is intended to be used as a
 [Libravatar](https://www.libravatar.org/) is a free service and an open
 specification for hosting profile images tied to email or OpenID addresses.
 
+**The default branch changed from `master` to `main` on 2022-06-11.**
+
 ## Features
 
 * Avatar delivery based on email addresses