#if not working after api update

Well, we know what pre processing statements are. However what exactly do you mean by they "don't work" anymore? Are you sure those two defines actually exists? Some installers may overwrite the script defines during installation. A quick google gave an example.

I don't have this package you have installed. However checking the assetstore page showed there should be a script called "CompilerDefine.cs" located at

 AwesomeTechnologies/VegetationStudioPro/Editor/Common/Editor/CompilerDefine.cs

I don't know what's in that script, but it may be the root of your issue.