diff --git a/packages/react-app-polyfill/README.md b/packages/react-app-polyfill/README.md
index 3243ad7b16e..52c299f24fe 100644
--- a/packages/react-app-polyfill/README.md
+++ b/packages/react-app-polyfill/README.md
@@ -13,6 +13,8 @@ Each polyfill ensures the following language features are present:
 1. `Symbol` (a built-in object used by `for...of` syntax and friends)
 1. `Array.from` (a built-in static method used by array spread, i.e. `[...arr]`)
 
+*If you need more features, you must include them manually.*
+
 ### Usage
 
 First, install the package using Yarn or npm: