(a) Any elector whose precinct or ward is changed by a change of ward or precinct boundaries must have notification mailed to him by the county board of voter registration and elections reflecting his new precinct or ward.

(b) Any area in the county annexed to a municipality which is divided into wards shall be made part of a ward to which it is contiguous by the county board of voter registration and elections. In the event the annexed area in a municipality divided into wards contains at least five hundred qualified electors the area annexed shall be made a separate ward which must be given a numerical designation. As soon as practicable following annexation, the board must mail all registered electors of record residing in the annexed area notification designating the number of the ward, if appropriate, and precinct to which they have been assigned.

(c) The envelope in which notifications mailed out in conjunction with the provisions of subsections (a) and (b) must have printed on the front "DO NOT FORWARD". All electors whose precinct or ward is changed by boundary changes must be added to the records of the precinct or ward to which they are assigned and deleted from those of the precinct or ward to which they were formerly assigned.