Compiled to .net 3.5 so it will work if you drop the dll into your unity porject.

Author: EricFreeman

src/UnityEventAggregator/UnityEventAggregator.csproj

@@ -9,8 +9,9 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>UnityEventAggregator</RootNamespace>
     <AssemblyName>UnityEventAggregator</AssemblyName>
-    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
+    <TargetFrameworkProfile />
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>