diff --git a/scripts/upgrade b/scripts/upgrade
index f3b0fb1..fb21700 100644
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -106,6 +106,21 @@ ynh_install_nodejs --nodejs_version=$nodejs_version
 
 #=================================================
 # SPECIFIC UPGRADE
+#=================================================
+# UPDATE A CONFIG FILE
+#=================================================
+ynh_script_progression --message="Updating a configuration file..."
+
+ynh_add_config --template="../conf/client.config.js" --destination="$final_path/src/client/config.js"
+
+chmod 400 "$final_path/src/client/config.js"
+chown $app:$app "$final_path/src/client/config.js"
+
+ynh_add_config --template="../conf/server.index.js" --destination="$final_path/src/server/index.js"
+
+chmod 400 "$final_path/src/server/index.js"
+chown $app:$app "$final_path/src/server/index.js"
+
 #=================================================
 # BUILD APP
 #=================================================