Portlets Generic Setup syntax changes
The original format for limiting a portlet to a certain type of manager was:
<portlet addview="portlets.BBB"
title="Foo"
description="Foo"
for="plone.app.portlets.interfaces.IColumn" />
but this form was deprecated in Plone 3.1 to allow multiple values in the for field. In Plone 4 the required form is:
<portlet title="Foo"
addview="portlets.New"
description="Foo">
<for interface="plone.app.portlets.interfaces.IColumn" />
<for interface="plone.app.portlets.interfaces.IDashboard" />
</portlet>

