According to No. 44 announcement from SAMR in 2019, manufacturers of the products listed in the annexed catalogue must apply for a CCC Self Declaration (SD) as of 1 January 2020.
Products under SD scheme that hold a CCC certificate shall alter to SD as of 1 November 2020. The official implementation rule is CNCA-00C-008:2019.
(The original announcement in Chinese can be found via this Link.)
* SAMR = State Administration for Market Regulation; CCC = China Compulsory Certification.