614.11  Admission in writing — new promise.
  Causes of action founded on contract are revived by an admission in writing, signed by the party to be charged, that the debt is unpaid, or by a like new promise to pay the same.
[C51, §1670; R60, §2751; C73, §2539; C97, §3456; C24, 27, 31, 35, 39, §11018; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §614.11]