At a command prompt in the VPOP3 directory run
psql
(The password is 'vpop3pass')
Then, type
select username,updateuser,updatetime from settingaudit inner join users.users on keyfield=usernumber::varchar where tablename='users.usersettings' and keyfield2='mainpassword' order by updatetime desc;
N.B. VPOP3 does not need to be stopped while you do this