json query problem

trying to select a row of json type returning the entire json record

table users id, jsondata
jsondata has {"username":"jdoe", ....}

select json_to_row from users where jsondata->"username" = "jdoe";
fails on operator -> unknown

using debian testing with postgresql backport ppa
psql: 9.3.2 server 9.2.6

do I need a higher server version ? is there a 9.3 server available for
debian ?