diff --git a/manual/upgrade/upgrade_docker.md b/manual/upgrade/upgrade_docker.md
index 64e4b49a..e0f7bb99 100644
--- a/manual/upgrade/upgrade_docker.md
+++ b/manual/upgrade/upgrade_docker.md
@@ -70,7 +70,9 @@ Then download the new `seafile-server.yml` according to the following commands:
     wget https://manual.seafile.com/13.0/repo/docker/pro/seasearch.yml
     ```
 
-#### Step 2.4) Download `.yml` file for seadoc
+#### Step 2.4) Download `.yml` file for SeaDoc (optional)
+
+If you use SeaDoc extension, the seadoc.yml file need to be updated too: 
 
 ```sh
 wget https://manual.seafile.com/13.0/repo/docker/seadoc.yml