This post shows you how to solve the problem

No way to resolve conflict between "System.IO.Compression, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" and "System.IO.Compression, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089". Choosing "System.IO.Compression, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" arbitrarily.

Or

Consider app.config remapping of assembly "System.IO.Compression, Culture=neutral, PublicKeyToken=b77a5c561934e089" from Version "4.0.0.0" [C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.6.2\System.IO.Compression.dll] to Version "4.2.0.0" [C:\Working\Source\FoxLearn.WCF\bin\Debug\System.IO.Compression.dll] to solve conflict and get rid of warning.

When rebuilding your project in the visual studio.

C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets(2110,5): warning MSB3276: Found conflicts between different versions of the same dependent assembly. Please set the "AutoGenerateBindingRedirects" property to true in the project file. For more information, see http://go.microsoft.com/fwlink/?LinkId=294190.

To fix the problem above you should open the app.config file, then modify your configuration as shown below.

<runtime>
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <dependentAssembly>
      <assemblyIdentity name="System.IO.Compression" publicKeyToken="b77a5c561934e089" culture="neutral" />
      <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.2.0.0" />
    </dependentAssembly>
  </assemblyBinding>
</runtime>