You should use Common.Logging.NLog20 but you'll have to add an assembly redirect :
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Common.Logging" publicKeyToken="af08829b84f0328e" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-2.1.2.0" newVersion="2.1.2.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="NLog" publicKeyToken="5120e14c03d0593c" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-2.1.0.0" newVersion="2.1.0.0" />
</dependentAssembly>
</assemblyBinding>
And your common logging config should look something like this :
<common>
<logging>
<factoryAdapter type="Common.Logging.NLog.NLogLoggerFactoryAdapter, Common.Logging.NLog20">
<arg key="configType" value="FILE" />
<arg key="configFile" value="~/NLog.config" />
</factoryAdapter>
</logging>
</common>
Thankfully the nuget packages for common.logging and adapters has changed (see here) You should be able to use the Common.Logging.NLog21 libarary.