With the permission of Kast !!
This is not an official update!
This is not a professional update!
I did this for myself while waiting for the official update!

What do you need to do?
1. Download – Tandem addon for RJL Scania rs&r4 by Kast
2. Download my fix
3. Open the RJL_Scania_tandem_addon_by_kast zip file
4. Delete the UNIT folder
5. Open my zip file
6. And you move the UNIT folder to the RJL_Scania_tandem_addon_by_kast zip file.

Link – RJL Tandem by Kast – https://forum.scssoft.com/viewtopic.php?t=246483
RJL Scania Fix by Mr. German Truck – https://sharemods.com/hpfbicpjw2te/RJL_1.40_fix.zip.html

I hope I’ve been helpful !

Credits:
kRipt Paintjob’s, Kast, Mr. German Truck, RJL