diff --git a/Cheat-Sheet.md b/Cheat-Sheet.md
index 806e0e7..80bb9f7 100644
--- a/Cheat-Sheet.md
+++ b/Cheat-Sheet.md
@@ -157,8 +157,6 @@ func (i *Image) Size() (width, height int)
 func (i *Image) SubImage(r image.Rectangle) image.Image
 ```
 
-(This function was introduced at Ebiten 1.9.0-alpha)
-
 `SubImage` returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.
 
 The returned value is always `*ebiten.Image`.