Object fields contain the string "null" rather than N for a NULL value.

There was a change in behavior in 2.2.8 from 2.2.7 where object fields which have NULL values are represented by the string "null" rather than by an actual NULL, N when serialized.

For example, Contact->prefix_id when NULL now contains the string "null". Same occurs with suffix_id, county_id, etc. when these are supposed to be integers. The same occurs with NULL varchar fields such as postal_code for an address.

This results in bugs I have to try and work around in custom code I have written to extend civiCRM for our data model.