Downgrade 4.12 to 4.9?

Hello! I recently bought an asset for “classic fps movement pack” that I found doesn’t work in 4.12.5. It included bunny hopping and other things found in source games. It wasn’t from this official site. The PDF telling me how to install it said it was updated for 4.9, but it did not specify if it wasn’t compatible with other versions when advertising itself. I’m way too far to go back from my current project and I understand that there are different file types between versions as illustrated in previous threads that I tried searching at but I just want security to know that this isn’t my fault that it isn’t working: that it’s just incompatible with the version. Thank you for your time!

(by the way I would post the code if it wasn’t that this asset wasn’t put up for profit. He is selling it, so I cannot distribute)

This is the movement system

Hi Sputnikcer,

I apologize for the delayed response. Projects and assets in later engine versions are not able to be used in previous engine versions. If the project is listed as 4.12 and has any asset that was made/imported in 4.12, that asset will not be compatible with 4.11 or prior engine versions.