Sage has updated their support knowledgebase to make it clear that there is no separate IRD ( Interim Release Download ) for Sage 100 2020.
These downloads are typically released in December and include updates to accommodate year-end tax changes.
According to Sage:
There is no end of year IRD (Interim Release Download) for the year-end 2020. This update was not needed for the 1099s as the changes for 2020 were made in the latest versions released with changes to the NEC (NonEmployee Compensation) Forms.
Make sure you have versions 2020.1, 2019.4, 2018.10 installed and the Aatrix forms have been updated.
If you have 3rd party modifications for Production Management or IRP see kb 107739
Changes to the Payroll versions are no longer done for year-end through the IRD but rather the Product Updates for Payroll. Latest version for year 2020 is Payroll v184.108.40.206.