How can i disable strong passwords?

In newer ispCP versions you can disable strong passwords (the enforcement of characters AND numbers) in the GUI: log in as admin and go to Settings → General Settings.

To disable them in older versions you have to do this: open /var/www/ispcp/gui/include/ispcp-lib.php and change the following option:

// enable or disable strong passwords
// false = disable, true = enable
$cfg['PASSWD_STRONG'] = false;

You can also set the minimum password lenght.

// password chars
$cfg['PASSWD_CHARS'] = 6;