Voters who fall into one of five categories will receive a notice. The categories are:
Voter has not voted since before the 2008 General Election.
Voter has the same last name, first initial, and birth date as another voter in the state.
First-class mailing sent to voter since January 1, 2009, was returned by the post office as undeliverable.
Voter surrendered Oklahoma driver license in another state.
Voter may have registered to vote in another state.