diff --git a/README.md b/README.md
index 51d7327..86bb6b4 100644
--- a/README.md
+++ b/README.md
@@ -55,3 +55,4 @@ ligatures only in sligeach_ligature.ttf
 Issues
 ----------------------------------------
  - ar & air are only ligaturized after some non-space characters and space(s).
+ - the font height is too high.