Some constants were deprecated in favour of enums

CasHelper::CA_* constants

CasHelper::CA_DEFAULT, CasHelper::CA_CUSTOM and CasHelper::CA_NONE constants are deprecated in favour of SslCertificateVerification enum:

enum SslCertificateVerification: int {

  // SSL configuration to use the system's CA bundle to verify CAS server.
  case Default = 0;

  // SSL configuration to use provided file to verify CAS server.
  case Custom = 1;

  // SSL Configuration to not verify CAS server.
  case None = 2;

}

CasLoginException constants

CasLoginException::NO_LOCAL_ACCOUNT, CasLoginException::SUBSCRIBER_DENIED_REG, CasLoginException::ACCOUNT_BLOCKED, CasLoginException::SUBSCRIBER_DENIED_LOGIN, CasLoginException::ATTRIBUTE_PARSING_ERROR, CasLoginException::USERNAME_ALREADY_EXISTS, and CasLoginException::ADMIN_APPROVAL_REQUIRED constants are deprecated in favour of CasLoginExceptionType enum:

enum CasLoginExceptionType: string {

  // Unknown exception.
  case Unknown = '';

  // Auto-registration turned off, and local account does not exist.
  case NoLocalAccount = 'message_no_local_account';

  // Auto-registration turned on, but subscriber denied auto-registration.
  case SubscriberDeniedRegistration = 'message_subscriber_denied_reg';

  // Could not log user in, because Drupal account is blocked.
  case AccountBlocked = 'message_account_blocked';

  // An event listener prevented login.
  case SubscriberDeniedLogin = 'message_subscriber_denied_login';

  // Error parsing CAS attributes during login.
  case AttributeParsingError = 'message_validation_failure';

  // Auto-registration attempted to register Drupal user that already exists.
  case UsernameAlreadyExists = 'message_username_already_exists';

  // Cannot log in until admins are not unblocking the new account.
  case AdminApprovalRequired = '[no message]';

}

Important change: If the third-party code called CasLoginException::getCode() they should adapt their code because, now, this method returns one of the CasLoginExceptionType enum cases instead of an integer.