diff --git a/docs/4.x/config/app.md b/docs/4.x/config/app.md
index 91514a3ea..9dd2dda59 100644
--- a/docs/4.x/config/app.md
+++ b/docs/4.x/config/app.md
@@ -452,13 +452,13 @@ If your queue driver supplies its own worker, set the , which means it will work natively in [load-balanced environments](kb:configuring-load-balanced-environments#mutex-locks).
-::: tip
-A [NullMutex](craft4:craft\mutex\NullMutex) driver is used when Dev Mode is enabled, since mutex drivers aren’t necessary for local development and we’ve seen issues with mutex in some Windows and Linux filesystems.
+::: warning
+Prior to 4.6, enabling `devMode` would automatically switch from the default `FileMutex` driver to a special `NullMutex` driver to help avoid some virtualization bugs. Now, `NullMutex` is only used when a database connection is not available (i.e. prior to installation).
:::
-You can configure a custom mutex driver by configuring the `mutex` component’s nested `$mutex` property:
+You can configure a custom mutex driver by overriding the `mutex` component’s nested `$mutex` property:
```php
// Use mutex driver provided by yii2-redis
@@ -487,7 +487,7 @@ return [
```
::: warning
-Pay careful attention to the structure, here—we’re only modifying the existing component’s `mutex` _property_ and leaving the rest of its config as-is.
+Pay careful attention to the structure of the configuration object: we’re only modifying the existing `mutex` component’s nested _driver_ property and leaving the rest of its config as-is. The mutex _component_ should always be an instance of ,
:::
## Modules