• I just tested this on my 2014 server and this is what I observed

    Running a query with trace flag 2312 will use version 120 (the new version) of the cardinality estimator when the database compatibility is 110 (SQL 2012)

    Running a query with trace flag 9481 will use version 70 (the old version) of the cardinality estimator when the database compatibility is 120 (SQL 2014)