Idaho Code § 31-1609
All appropriations, other than appropriations for incompleted improvements in progress of construction, shall lapse at the end of the fiscal year; provided, that the appropriation accounts may remain open until the first Monday in November for the payment of claims incurred against such appropriations prior to the close of the fiscal year. After the said first Monday in November the appropriations, except as herein provided regarding incompleted improvements, shall become null and void and any lawful claims presented thereafter against any such appropriations shall be provided for in the next ensuing budget. All balances in any appropriation for incomplete improvements in progress of construction, shall be carried forward and shown in the budget for the ensuing year to the credit of such improvement.
Idaho Code § 31-1609