Upgrading guide for uploadfield

docs/en/02_Developer_Guides/07_Debugging/03_Template_debugging.md

@@ -10,7 +10,7 @@ to track down a template or two. The template engine can help you along by displ
 source code comments indicating which template is responsible for rendering each 
 block of html on your page.
 
-	::::yaml
+	:::yaml
 	---
 	Only:
 	  environment: 'dev'

docs/en/04_Changelogs/4.0.0.md

@@ -267,6 +267,47 @@ instead, or if used in an actual XML file use `.CDATA` (see [template casting](/
 
 Where your code once used SQLQuery you should now use SQLSelect in all cases, as this has been removed (check the [3.2.0](3.2.0) upgrading notes).
 
+#### Upgrade code that uses UploadField
+
+This field has been superceded by a new class provided by the
+[asset-admin](https://github.com/silverstripe/silverstripe-asset-admin) module, which provides a more
+streamlined simpler mechanism for uploading File dataobjects.
+
+A helper service `FileHandleField` is provided to assist with dependency injection. Where the asset-admin
+module is not installed this service will fall back to the `FileField` class instead.
+
+Usages of UploadField will need to be upgraded as below:
+
+3.x code
+
+
+    :::php
+    class MyClass extends DataObject {
+        public function getCMSFields() {
+            return new FieldList(
+                new UploadField('Files')
+            );
+        }
+    }
+
+
+4.x code
+
+
+    :::php
+    use SilverStripe\ORM\DataObject;
+    use SilverStripe\Forms\FieldList;
+    use SilverStripe\Forms\FileHandleField;
+    
+    class MyClass extends DataObject {
+        public function getCMSFields() {
+            return FieldList::create(
+                Injector::inst()->create(FileHandleField::class, 'Files')
+            );
+        }
+    }
+
+
 #### Upgrade code that uses i18n
 
 In many cases, localisation strings which worked in 3.x will continue to work in 4.0, however certain patterns