Cal. INS § 10199.44

(a) On or after January 1, 1994, every insurer issuing, amending, or renewing group disability insurance which covers hospital, medical, or surgical expenses shall notify the group policyholders in writing of the cancellation of the group policy and shall include in their contract with group policyholders, regardless of the situs of that contract, a provision requiring the group policyholder to mail promptly to each person covered under the group policy a legible, true copy of any notice of cancellation of the policy which may be received from the insurer and to provide promptly to the insurer proof of that mailing and the date thereof.

(b) The notice of cancellation required by subdivision (a) shall include information regarding the conversion rights of persons covered under the group policy upon termination of the group policy. This information shall be in clear and easily understandable language.