In order to use an older reference file from Kodak, you will need to identify first which file to use.
For current high quality targets from LaserSoft Imaging has a barcode that can be read by SilverFast.
The corresponding reference file is thus automatically identified.
If you do not have a target with such a barcode (like older ones from Kodak), SilverFast Ai Studio will ask you for which reference file data it should compare the readings from the scanner with.
To help you determine which reference file to download for your target, here are naming examples for the type:
R210113 - Reflective targets
T210111 - Transparency targets (4x5" and 6x7cm)
E310112 - 35mm transparency targets on Ektachrome 3 material
The data can usually also be seen in the file name directly:
E1200706.Q60 - meaning Ektachrome (1) film, from 2007, June (06)
These Q60 files are standard text files, just don't carry the TXT extension.
You can still open them normally in a text editor, if you are unsure if you've selected the correct file.
Here you will find the date of production and further information in more readily understandable format.
While the original source on Kodak's FTP server is no longer available online, there are a number of other resources to go to, e.g. X-Rite:
https://www.xrite.com/de/service-support/downloads/k/kodak-it8-q60-reference-files-2003-2007
You can respectively use either the "PC Version" or "Mac version" download option there.