Ala. Code § 16-13-103
Warrants reciting that they are issued pursuant to the terms of this article shall in any action or proceeding involving their validity be conclusively deemed to be fully authorized thereby and to have been issued, sold, executed and delivered in conformity therewith and with all other provisions of law applicable thereto and shall be incontestable, anything herein or in other statutes to the contrary notwithstanding, unless such action or proceeding is begun before or within 30 days after the day upon which the warrants are delivered and paid for, and no irregularity in the proceedings to authorize the issue of warrants hereunder nor the omission or neglect of any officer charged with the execution of any duties imposed by this article shall affect the validity of any warrants issued hereunder; provided, that the issuance of such warrants shall have been approved by the State Superintendent of Education.
Ala. Code § 16-13-103 (1975)