Hi @AnkH - It works successfully using MSFS Addons Linker. With both MSFS 2020 and 2024 installed, MSFS Addons Linker saves the trouble and disk space of installing scenery folders twice. Set your underlying addon file structure with 3 folders something like this and then you can easily test out existing MSFS 2020 addons in MSFS2024
MSFS2020 Only
MSFS2024 Compatible
MSFS2024 Only
Here's a link to how my directory structure translates to addons in MSFS Addons Linker
So, as long as you've got PacSim RKSI currently installed in MSFS 2020, it should work for you in MSFS 2024 using this method... NB: the first time RKSI loads in MSFS2024 took about 5 minutes - I think because it includes a large aerial image file of the area surrounding the airport