code: def _require_version(self, major, minor=0):
          
          new_ver = (major, minor)
          if self.ykver and new_ver > self.ykver:
              raise yubikey_base.YubiKeyVersionError('Configuration requires YubiKey %d.%d, and this is %d.%d'
                                                % (major, minor, self.ykver[0], self.ykver[1]))
          if new_ver > self.yk_req_version:
              self.yk_req_version = new_ver
docs: Update the minimum version of YubiKey this configuration can be applied to.