CPAO CPAO/IT&Tech/Revision(7th CPC)/19.Vol-III (E)/2018-19/95 29.08.2018 Office Memorandum Subject: Mandatory use of Digital Signature – Regarding. Reference is invited to this office OM No. CPAO/IT&Tech/Revision (7th CPC)/19.Vol-lII/ 2016-17/37 dated 25.05.2017