Get Letest assembly at runtime

 I have tested for Ajax, it works fine

 

<runtime>

    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Extensions"             
                                     publicKeyToken="31bf3856ad364e35"/>

        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>

      </dependentAssembly>

      <dependentAssembly>

        <assemblyIdentity name="System.Web.Extensions.Design"
                                    publicKeyToken="31bf3856ad364e35"/>

        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>

      </dependentAssembly>

    </assemblyBinding>

  </runtime>