Ill. Admin. Code tit. 38, § 100.60 – Service

a) Service of any document may be by mail or by personal delivery upon any person or entity. Service of any document may also be made by email on a Party's counsel of record or an unrepresented Party if one or more email addresses are provided pursuant to subsections (a)(1) through (3). Service by email to the assigned Department counsel must be addressed to the counsel's email address appearing on any pleading and any secondary Department email addresses provided on any pleading.
1. 1) At any time either before or after issuance of a Hearing notice, the Department may require a Party's counsel of record to provide one or more email addresses at which they will accept service of documents in connection with the Hearing.
2. 2) At any time either before or after issuance of a Hearing notice, the Department may request, but not require, an unrepresented Party to accept service by email of documents in connection with the Hearing by designating one or email addresses at which they will accept service.
3. 3) If any secondary email address is designated by a Party, the Department must serve the documents to both the designated primary and secondary email addresses.
b) Proof of service by mail or personal delivery will be attached to the original of any document served. Proof of service by email shall be the emailed notice to which the document is attached. In the absence of evidence to the contrary, the date shown on the proof of service shall be deemed the date of service. Proof of service may be verified by certification as provided for in Section 1-109 of the Code of Civil Procedure [735 ILCS 5].
c) If service is by email, the Department will maintain a copy of the sent email and will verify within one business day that the transmission of the email has not failed or been rejected. In the event of rejection or failure, absent correction of an erroneous email address, service shall be made by mail or personal delivery.
d) Any Party may provide an updated mailing address and/or email address for receipt of service of documents at any point during a proceeding by sending notice of the updated mailing address and/or email address to all Parties of record.
e) Documents containing information that could reasonably be deemed personal, proprietary, confidential, or trade secret information or containing any other information listed under 5 ILCS 100/10-75(b) will be served by mail, personal delivery, or a secure messaging or file transfer system approved by the Secretary.