diff --git a/tryton.cfg b/tryton.cfg
index 46c759e..b889f2d 100644
--- a/tryton.cfg
+++ b/tryton.cfg
@@ -2,8 +2,9 @@
 version=4.3.0
 depends:
     ir
-    activity
     smtp
+extras_depend:
+    activity
 xml:
     electronic_mail.xml
     template.xml