DOE had previously approved the use of listed software validated against RESNET Publication 001-2016 in 45L tax credit certifications for homes with building permits dated on/before 12/31/2020. This memo extends the timeframe during which DOE-listed software validated against RESNET 001-2016 may be used for 45L certifications, to homes with building permits dated on/before 6/30/2021. This revised cutoff date is now reflected in DOE’s Approved Software List.