diff --git a/addons/project/doc/stage_status.rst b/addons/project/doc/stage_status.rst
index f02b3eddbaa..cc2a64c2fbf 100644
--- a/addons/project/doc/stage_status.rst
+++ b/addons/project/doc/stage_status.rst
@@ -47,8 +47,9 @@ The following subtypes are triggered on ``project.task``:
 
  - ``mt_task_new``: new tasks. Condition: ``obj.stage_id and obj.stage_id.sequence == 1``
  - ``mt_task_stage``: stage changed. Condition: ``obj.stage_id and obj.stage_id.sequence != 1``
- - ``mt_task_assigned``: TODO
- - ``mt_task_blocked``: TODO
+ - ``mt_task_assigned``: user assigned. condition: ``obj.user_id and obj.user_id.id``
+ - ``mt_task_blocked``: kanban state blocked. Condition: ``obj.kanban_state == 'blocked'``
+
 
 Those subtypes are also available on the ``project.project`` model and are used
 for the auto subscription.
diff --git a/addons/project_issue/doc/changelog.rst b/addons/project_issue/doc/changelog.rst
new file mode 100644
index 00000000000..e74516f1600
--- /dev/null
+++ b/addons/project_issue/doc/changelog.rst
@@ -0,0 +1,13 @@
+.. _changelog:
+
+Changelog
+=========
+
+`trunk (saas-2)`
+----------------
+
+- Stage/state update
+
+  - ``project.issue``: removed inheritance from ``base_stage`` class and removed
+    ``state`` field. Added ``date_last_stage_update`` field holding last stage_id
+    modification. Updated reports.
diff --git a/addons/project_issue/doc/index.rst b/addons/project_issue/doc/index.rst
new file mode 100644
index 00000000000..9e12eef2124
--- /dev/null
+++ b/addons/project_issue/doc/index.rst
@@ -0,0 +1,22 @@
+=====================
+Project Issue DevDoc
+=====================
+
+Project Issue module documentation
+===================================
+
+Documentation topics
+''''''''''''''''''''
+
+.. toctree::
+   :maxdepth: 1
+   
+   stage_status.rst
+
+Changelog
+'''''''''
+
+.. toctree::
+   :maxdepth: 1
+
+   changelog.rst
diff --git a/addons/project_issue/doc/stage_status.rst b/addons/project_issue/doc/stage_status.rst
new file mode 100644
index 00000000000..6afd4508cd9
--- /dev/null
+++ b/addons/project_issue/doc/stage_status.rst
@@ -0,0 +1,54 @@
+.. _stage_status:
+
+Stage and Status
+================
+
+.. versionchanged:: 8.0 saas-2 state/stage cleaning
+
+Stage
++++++
+
+This revision removed the concept of state on project.issue objects. The ``state``
+field has been totally removed and replaced by stages, using ``stage_id``. The
+following models are impacted:
+
+ - ``project.issue`` now use only stages. However a convention still exists about
+   'New' stage. An issue is consdered as ``new`` when it has the following
+   properties:
+
+   - ``stage_id and stage_id.sequence = 1``
+
+ - ``project.task.type`` do not have any ``state`` field anymore. 
+ - ``project.issue.report`` do not have any ``state`` field anymore. 
+
+By default a newly created issue is in a new stage. It means that it will
+fetch the stage having ``sequence = 1``. Stage mangement is done using the
+kanban view or the clikable statusbar. It is not done using buttons anymore.
+
+Stage analysis
+++++++++++++++
+
+Stage analysis can be performed using the newly introduced ``date_last_stage_update``
+datetime field. This field is updated everytime ``stage_id`` is updated.
+
+``project.issue.report`` model also uses the ``date_last_stage_update`` field.
+This allows to group and analyse the time spend in the various stages.
+
+Open / Assignation date
++++++++++++++++++++++++
+
+The ``date_open`` field meaning has been updated. It is now set when the ``user_id``
+(responsible) is set. It is therefore the assignation date.
+
+Subtypes
+++++++++
+
+The following subtypes are triggered on ``project.issue``:
+
+ - ``mt_issue_new``: new tasks. Condition: ``obj.stage_id and obj.stage_id.sequence == 1``
+ - ``mt_issue_stage``: stage changed. Condition: ``obj.stage_id and obj.stage_id.sequence != 1``
+ - ``mt_issue_assigned``: user assigned. condition: ``obj.user_id and obj.user_id.id``
+ - ``mt_issue_blocked``: kanban state blocked. Condition: ``obj.kanban_state == 'blocked'``
+
+Those subtypes are also available on the ``project.project`` model and are used
+for the auto subscription.