how to migrate a multi-value term reference field?
Yes. The migration of term doesn't allow to migrate multi-value. You have to process the source ahead.


Create a new migration and import the data to terms of vocabulary named 'voc_features' at first.
Add a dependence to your current migration using previous migration. Such as $this-&gt;dependencies = array('MigrateXXXMigration');.
The field mapping should be like this,$this-&gt;addFieldMapping('field_features', 'Features')-&gt;arguments(array('source_type' =&gt; 'tid'));
In the function prepareRow($row), you should prepare the Features field and put it into your $row variable. $row-&gt;Features=array(tid1,tid2,tid3);. The 'tid1','tid2' and 'tid3' should be replace the live tid from your term tables.