I'm wondering if someone has created or adjusted this extension to work in OutSystems 9 on the .Net 3.5 already.
I have fixed it my self, I will add the steps below for someone that decides to use this extention on Outsystems 9 or 10 in the future.
It took 3 main steps:
1 . Changed the compiler version of Integration Studio to .NET 4.0.XXX to match the target .net version from the target environment .NET (your OutSytems 9 environment).
2. Open the extension in MS Visual Studio and go to the reference section, remove the WindowsBase reference and add the WindowsBase reference back, but this time it will add the one of the .NET 4.0.
3. go to build -> build solution.
3.1. Save the solution
3.2. Go back to integration Studio -> verify
3.3. then Upload
3.4 Then pulbish