Any warrant issued prior to January 1, 1998, shall be governed by the law effective on the date of issue of the warrant. Any warrant issued on or after January 1, 1998, shall be governed by the one-year period of negotiability specified in Section 17070.
Source:
Section 17070.1, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV§ionNum=17070.1..