plesk create/edit service doesnt allow username with numbers anymore

[si458]

Hi,

ive been able to track a bug with the plesk module

if you try creating a service or editing a service which includes a username with numbers in,

blesta just returns the error 'the username must be in lowercase'

the bug is inside the plesk.php file around line 407

'format' => [
  'if_set' => true,
  rule' => function ($username) {
    return ctype_lower($username);
  },
  'message' => Language::_('Plesk.!error.plesk_username.format', true)
]

ctype_lower will always return false if the string includes numbers https://www.php.net/manual/en/function.ctype-lower.php#refsect1-function.ctype-lower-examples

my example are my domains which i own and they are 'si458.co.uk' and 'si458.com'

i try setting the username as si458couk but always returns an error

Regards

Simon