diff --git a/docs/migration.md b/docs/migration.md
index effbc90a5dcfa4b62c02b04266a61858d60a0475..9cc310dcc569b2e7eb94287dc5b062b4a217f983 100644
--- a/docs/migration.md
+++ b/docs/migration.md
@@ -151,6 +151,11 @@ Dropped entirely for the new card component.
 - Added `.pull-{xs,sm,md,lg,xl}-{left,right,none}` classes for responsive floats
 - Removed `.pull-left` and `.pull-right` since they're redundant to `.pull-xs-left` and `.pull-xs-right`
 
+### Vendor prefix mixins
+Bootstrap 3's [vendor prefix](http://webdesign.about.com/od/css/a/css-vendor-prefixes.htm) mixins, which were deprecated in v3.2.0, have been removed in Bootstrap 4. Since we use [Autoprefixer](https://github.com/postcss/autoprefixer), they're no longer necessary.
+
+Removed the following mixins: `animation`, `animation-delay`, `animation-direction`, `animation-duration`, `animation-fill-mode`, `animation-iteration-count`, `animation-name`, `animation-timing-function`, `backface-visibility`, `box-sizing`, `content-columns`, `hyphens`, `opacity`, `perspective`, `perspective-origin`, `rotate`, `rotateX`, `rotateY`, `scale`, `scaleX`, `scaleY`, `skew`, `transform-origin`, `transition-delay`, `transition-duration`, `transition-property`, `transition-timing-function`, `transition-transform`, `translate`, `translate3d`, `user-select`
+
 ## Documentation
 
 Our documentation received an upgrade across the board as well. Here's the low down: