diff --git a/INSTALL b/INSTALL
index 318f5fd8e8..5220d7a5b1 100644
--- a/INSTALL
+++ b/INSTALL
@@ -7,8 +7,10 @@ Prerequisites
  * Python 2.7 or later (http://www.python.org/)
  * trytond (http://www.tryton.org/)
  * trytond_account (http://www.tryton.org/)
+ * trytond_account_product (http://www.tryton.org/)
  * trytond_product (http://www.tryton.org/)
  * trytond_account_invoice (http://www.tryton.org/)
+ * Optional: trytond_purchase (http://www.tryton.org/)
 
 Installation
 ------------