New Post: BCL error with libraries

Any attempt of use Tweetinvi package in a .Net4 targeted class library (incuded WCF Service Library) throws a lot of this errors (as warnings but it doesnt compile):

Warning 6 The primary reference "Microsoft.Threading.Tasks" could not be resolved because it has an indirect dependency on the framework assembly "System.Runtime, Version=1.5.11.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which could not be resolved in the currently targeted framework. ".NETFramework,Version=v4.0". To resolve this problem, either remove the reference "Microsoft.Threading.Tasks" or retarget your application to a framework version which contains "System.Runtime, Version=1.5.11.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a". WcfServiceLibrary4
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