In the Canton of Zurich, the Accession Act to the IVöB 2019 and the Cantonal Submission Ordinance came into force on October 1, 2023. The new law therefore applies to new tenders with immediate effect, while the old law still applies as a transitional right for procedures initiated before October 1, 2023.
More on this at:
https://www.zh.ch/de/politik-staat/kanton/kantonale-verwaltung/beschaffung-einkaeufe.html