Validation does not exist: regex.
I am getting error: "Validation does not exist: regex."
Looking in library\core\class.validation.php:478
I note that if I provide $Rule as 'regex:' rule name will become $RuleName = 'regex' and on line 497 will be checked function_exists($RuleName).
As PHP has no regex function it will be always false.
Please confirm that ValidateRule('AuthenticationKey', 'regex:
^[a-z0-9_-]+$i', T('The client id must contain only letters, numbers and dashes.'))
will be always false.
I am looking in v2.0.18