Add a paragraph in 1.7.5 changes page about the _legacy_link

src/content/1.7/modules/core_updates/1.7.5.md

@@ -45,6 +45,33 @@ public function hookdisplayFooterProduct($params)
 }
 ```
 
+## About getAdminLink and _legacy_link
+
+The 1.7.5 version offers a conversion from legacy links to new migrated Symfony pages. Meaning if you use the `Link::getAdminLink`
+method somewhere in your modules to access a page that has been migrated, PrestaShop automatically converts it to the new Symfony
+migrated url.
+
+This prevents module developer to update their links each time a page has been migrated. However in many places the method is not
+used with the url parameters as arguments. Parameters are concatenated after the getAdminLink call. This can result in wrong conversion
+use cases, so you might need to refactor the way you use this method.
+
+Example:
+
+```php
+    //You shouldn't write
+    $link->getAdminLink('AdminOrders') . '&id_order={$order->id|intval}&vieworder';
+
+    //But rather
+    $link->getAdminLink('AdminOrders', true, [], ['id_customer' => $customer->id|intval, 'viewcustomer' => 1]);
+```
+
+Although this won't be a problem for legacy controllers, but as they will get migrated getAdminLink won't work any more
+if it is not used properly, so we advice you to refactor your getAdminLink beforehand.
+
+You can find more details about this new feature in the [Controller and Routing][controller-routing] page. 
+
 **Links:**
 
 * [Related issue on module Google Ananlytics (GitHub)](https://github.com/PrestaShop/ps_googleanalytics/pull/14/files)
+
+[controller-routing]: {{< relref "1.7/development/architecture/migration-guide/controller-routing.md#more-about-the-legacy-link-property" >}}