"For [assistance-eligible individuals (AEIs)] whose subsidies will expire on Sept. 30, 2021, notices must be sent between Aug. 16 and Sept. 15, 2021. Subsidy expiration notices must, at a minimum, include the following information: [1] A prominent identification of the date the subsidy will expire. [2] A statement that the AEI may be eligible for coverage without a subsidy through COBRA or coverage under a group health plan. The [DOL] has provided a model notice."