diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50bd87e9..a06a89ed 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ Features
 - Added `let-syntax` and `letrec-syntax` to the compiler and interpreter.
 - Added the `(scheme repl)` library and `interaction-environment` function from R7RS.
 - Allow `eval` to recognize `syntax-rules` macros.
+- Added single-byte oriented I/O functions `read-u8`, `peek-u8`, and `write-u8` from R7RS.
 
 Internal Changes