diff --git a/README.md b/README.md
index 9eed850..f5dcdd6 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,8 @@ by scanning directory patterns recursively.
 It modifies all source files in place and avoids adding a license header
 to any file that already has one.
 
+addlicense requires go 1.16 or later.
+
 ## install
 
     go get -u github.com/google/addlicense