diff --git a/README.rst b/README.rst
index e950c8616..54420026f 100644
--- a/README.rst
+++ b/README.rst
@@ -55,10 +55,10 @@ The following external libraries are provided with Modoboa:
 .. |latest-version| image:: https://img.shields.io/pypi/v/modoboa.svg
    :target: https://pypi.python.org/pypi/modoboa/
    :alt: Latest version on Pypi
-.. |landscape| image:: https://landscape.io/github/tonioo/modoboa/master/landscape.svg?style=flat
-   :target: https://landscape.io/github/tonioo/modoboa/master
+.. |landscape| image:: https://landscape.io/github/modoboa/modoboa/master/landscape.svg?style=flat
+   :target: https://landscape.io/github/modoboa/modoboa/master
    :alt: Code Health
-.. |travis| image:: https://travis-ci.org/tonioo/modoboa.png?branch=master
-   :target: https://travis-ci.org/tonioo/modoboa
-.. |codecov| image:: http://codecov.io/github/tonioo/modoboa/coverage.svg?branch=master
-   :target: http://codecov.io/github/tonioo/modoboa?branch=master
+.. |travis| image:: https://travis-ci.org/modoboa/modoboa.png?branch=master
+   :target: https://travis-ci.org/modoboa/modoboa
+.. |codecov| image:: http://codecov.io/github/modoboa/modoboa/coverage.svg?branch=master
+   :target: http://codecov.io/github/modoboa/modoboa?branch=master
diff --git a/doc/upgrade.rst b/doc/upgrade.rst
index 2dd849b87..8e9644f54 100644
--- a/doc/upgrade.rst
+++ b/doc/upgrade.rst
@@ -87,6 +87,12 @@ Specific instructions
 1.6.0
 =====
 
+.. warning::
+
+   You have to upgrade extensions due to `core.User` model attribute change (`user.group` to `user.role`).
+   Otherwise, you will have an internal error after upgrade.
+   In particular: `modoboa-amavisd https://github.com/modoboa/modoboa-amavis/commit/35df4e48b124e56df930cda8c013af0c1fcaabf3`_, `modoboa-stats https://github.com/modoboa/modoboa-stats/commit/aa4a39ce65eb306ad6dec30a54eb58945b120274`_, `modoboa-postfix-autoreply <https://github.com/modoboa/modoboa-postfix-autoreply/commit/20f98c8d1c0c0dbd420f47aefcbb0290022414a4>`_ are concerned.
+
 An interesting feature brougth by this version is the capability to
 make different checks about MX records. For example, Modoboa can
 query main `DNSBL <https://en.wikipedia.org/wiki/DNSBL>`_ providers