(1) Written notice of a determination of insured status shall be furnished to the claimant promptly. Such notice shall include a statement as to whether the claimant is an insured worker, the amount of wages for insured work paid to him by each employer during his base period, and the employers by whom such wages were paid. For an insured worker the notice shall include also his benefit year, his weekly benefit amount, and the maximum amount of benefits that may be paid to him for his unemployment during such year; for a worker who is not insured, the notice shall include the reason for such determination.

(2) The claimant, his most recent employer, and any employer whose account may be affected by adjudication of the claim shall be promptly notified in writing of the initial determination, any amended initial determination, or redetermination and the reasons therefor.