diff --git a/docs/4.0/migration.md b/docs/4.0/migration.md
index 7b4199fa0..393063937 100644
--- a/docs/4.0/migration.md
+++ b/docs/4.0/migration.md
@@ -10,6 +10,7 @@ toc: true
 While in beta, we aim to have no breaking changes. However, things don't always go as planned. Below are the breaking changes to bear in mind when moving from Beta 1 to Beta 2.
 
 - Removed `$badge-color` variable and its usage on `.badge`. We use a color contrast function to pick a `color` based on the `background-color`, so the variable is unnecessary.
+- Renamed `grayscale()` function to `gray()` to avoid breaking conflict with the CSS native `grayscale` filter.
 
 
 ## Summary