diff --git a/documentation/guides/migrating-from-v8-to-v9.md b/documentation/guides/migrating-from-v8-to-v9.md
index 053ee332132..dab2adb23dd 100644
--- a/documentation/guides/migrating-from-v8-to-v9.md
+++ b/documentation/guides/migrating-from-v8-to-v9.md
@@ -121,6 +121,8 @@ A list of functions/mixins and their value equivalents or new token values.
 | `border-radius()`<br>`border-radius(base)` | `--p-border-radius-base`  |
 | `border-radius(large)`                     | `--p-border-radius-large` |
 
+#### `border-width()`
+
 #### `duration()`
 
 | Function                         | Replacement Value/Token |
@@ -217,6 +219,28 @@ We replaced a few of the following filter function instances with color tokens i
 | `font-family()`<br>`font-family($family: base)` | `--p-font-family-sans`  |
 | `font-family($family: 'monospace')`             | `--p-font-family-mono`  |
 
+#### `high-contrast-border()`
+
+| Mixin                                                          | Replacement Value/Token                              |
+| -------------------------------------------------------------- | ---------------------------------------------------- |
+| `@include high-contrast-border`                                | `border: var(--p-border-width-1) solid transparent;` |
+| `@include high-contrast-border($border-width: <border-width>)` | `border: <border-width> solid transparent;`          |
+
+For `<border-width>` instances that are functions, see the [`border-width()`](#border-width) section for replacing it.
+
+For `<border-width>` instances that are hard coded values, see if you can replace it with one of our [new border-width tokens](https://github.com/Shopify/polaris-react/blob/77e8669595a4964ff5ce399967661a7621ea2a4d/src/tokens/token-groups/shape.json), otherwise leave it hardcoded.
+
+#### `high-contrast-outline()`
+
+| Mixin                                                           | Replacement Value/Token                               |
+| --------------------------------------------------------------- | ----------------------------------------------------- |
+| `@include high-contrast-outline`                                | `outline: var(--p-border-width-1) solid transparent;` |
+| `@include high-contrast-outline($border-width: <border-width>)` | `outline: <border-width> solid transparent;`          |
+
+For `<border-width>` instances that are functions, see the [`border-width()`](#border-width) section for replacing it.
+
+For `<border-width>` instances that are hard coded values, see if you can replace it with one of our [new border-width tokens](https://github.com/Shopify/polaris-react/blob/77e8669595a4964ff5ce399967661a7621ea2a4d/src/tokens/token-groups/shape.json), otherwise leave it hardcoded.
+
 #### `ms-high-contrast-color()`
 
 | Function                                             | Replacement Value/Token |