Section 85.20. Demand for payment

a. In any case where a demand for payment
  is  required  as  a  condition  precedent to the doing of any act or the
  commencement of any action or special  proceeding  pursuant  to  section
  85.10 of this title, the demand shall comply with the provisions of this
  section.
    b.  The  demand  shall  be in writing, sworn to by or on behalf of the
  claimant, and shall set forth:(1) the name and  post-office  address  of
  each  claimant,  and  of his attorney, if any; (2) the contract, debt or
  obligation involved; (3) the nature and basis of the claim; (4) the time
  when the claim arose; (5) the items  of  damage  claimed  to  have  been
  sustained  so  far  as  then  practicable; and (6) the nature of the act
  proposed to be done or of the action or special proceeding  proposed  to
  be commenced by the claimant.
    c.  The  demand  shall  be served on the municipality against whom the
  claim is made by delivering a copy thereof, in duplicate, personally, or
  by registered mail, to the person, officer, agent,  clerk  or  employee,
  designated  by  law  as  a  person to whom a summons in an action in the
  supreme court issued against such municipality may be delivered.
    d. Anytime after the date of service of the demand for payment and  at
  or  before  the  trial  of  an  action  or  the  hearing  upon a special
  proceeding to which the provisions of this  section  are  applicable,  a
  mistake,  omission,  irregularity  or  defect  made in good faith in the
  demand required to be served by this  section,  not  pertaining  to  the
  manner  or  time  of  service  thereof,  may  be corrected , supplied or
  disregarded, as the case  may  be,  in  the  discretion  of  the  court,
  provided  it  shall  appear  that  the  other  party  was not prejudiced
  thereby. Application for such relief, if made before trial  or  hearing,
  shall  be by motion, on affidavits; if made before the action or special
  proceeding is commenced, shall be by motion,  on  the  petition  of  the
  claimant,  or someone on his behalf. Failure to serve more than one copy
  may be corrected by such motion.