Audio Unity-Technologies-nativeaudioplugins-a0359a9c692f.zip language incompatibility errors

I'm trying to open the unity project from Unity-Technologies-nativeaudioplugins-a0359a9c692f.zip, and I'm seeing language incompatibility errors:

.../Unity-Technologies-nativeaudioplugins/Library/PackageCache/com.unity.textmeshpro@2.0.0/Scripts/Runtime/FastAction.cs(24,45): error CS1644: Feature `out variable declaration' cannot be used because it is not part of the C# 4.0 language specification

When I open the C# project that comes with this in Visual Studio 2019, it doesn't flag these errors. I assume that's because these Libraries aren't directly referenced by the demo scripts. The error message seems to indicate that the library scripts are being built with C# 4.0, which is very old.

Is there any way to load this project in recent versions of Unity? I'm using Unity 2019.1.2f1.

 

the scripts use *newer* c# features and the project has .net 3.5 runtime set - switch to 4.x runtime in player settings

[ or alternatively you can probably remove TMPro package - or any other which uses newer c# features - if they are not needed ]

you will need to install free substance plugin from asset store for substances to work, too, since their support was removed meanwhile

 

moreover I recommend *cloning* the project, not downloading the archive
nevertheless, there were some weird scene serialization errors still though - opening in 2017 LTS, and afterwards upgrading project to 2018 LTS before opening in 2019 might fix them