If USCIS determines that there are more immigrant visas available for a fiscal year than there are known applicants for such visas, USCIS will state whether you may use the Dates for Filing Visa Applications.
Otherwise, they will indicate that you must use the Application Final Action Dates to determine when you may file your adjustment of status application.
See the following link here for the month of November 2019:
https://www.uscis.gov/visabulletininfo
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