diff --git a/docs/en/03_Upgrading/index.md b/docs/en/03_Upgrading/index.md
index f5e75db52..a40bac43c 100644
--- a/docs/en/03_Upgrading/index.md
+++ b/docs/en/03_Upgrading/index.md
@@ -114,6 +114,16 @@ cd ~/my-project-root
 ~/.composer/vendor/bin/upgrade-code upgrade ./app/src --write
 ```
 
+### Switching to new `app/src` structure
+
+The `reorganise` command can automatically rename the `mysite` and `code` folder for you. It will search your code and find any occurence of `mysite`. It won't replace those occurence with `app` however.
+
+After installing, run the upgrader reorganise command:
+```
+cd ~/my-project-root
+~/.composer/vendor/bin/upgrade-code reorganise --write
+```
+
 ## Migrating files
 
 Since the structure of `File` dataobjects has changed, a new task `MigrateFileTask`
diff --git a/docs/en/04_Changelogs/4.2.0.md b/docs/en/04_Changelogs/4.2.0.md
index a021010ae..4bb9a41f8 100644
--- a/docs/en/04_Changelogs/4.2.0.md
+++ b/docs/en/04_Changelogs/4.2.0.md
@@ -135,10 +135,16 @@ Code which relies on raw SQL queries to these tables will need to be updated.
 
 `SiteTreeFileExtension` is deprecated, and has it's functionality baked directly into `File` dataobject.
 
-### New upgrader command
-The SilverStripe upgrader tool can now be used to convert your `_ss_environment.php` file to an equivalent `.env` file when migrating a SilverStripe 3 project to SilverStripe 4.
+### New upgrader commands
+
+Two new commands have been added to the SilverStripe upgrader tool: `environment` and `reorganise`.
+
+`environment` allows you to convert your `_ss_environment.php` file to an equivalent `.env` file when migrating a SilverStripe 3 project to SilverStripe 4.
+
+`reorganise` renames your `mysite` and `mysite/code` folders to `app` and `app/src`. It also warns you of any occurence of `mysite` in your codebase.
 
 ```
 cd ~/my-project-root
 upgrade-code environment --write
+upgrade-code reorganise --write
 ```