[RCD] $rcmail_config['login_lc'] explanation

hi,

can someone shed some light on the main.inc.php config option

$rcmail_config['login_lc'] = false;

i have only lower case login names (login = full email address) and stumbled over the problem that, somewhere along the way to 0.5 final, my users created Office@domain.at or kathrin.Maier@domain.tld

a user now now tried to log in via "office@domain.at" and got an error because "Office@domain.at" already existed. Office@domain.at worked without any problem.

i do not quite understand if i need this to be true or false. what i want: forced lowercase for at least all roundcube usernames.

thanks, raoul