Updating only .dll of a reference in my ASP.NET Application

I have a deployed web application project that references my Utility.dll class library. I want to make a change to the Utlity.dll and roll only that .dll out. The problem is that when I do that, I get the following error when I try to launch my site:

Could not load file or assembly 'Utility, Version=1.0.0.0, Culture=neutral, PublicKeyToken=3766481cef20a9d1' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Is there a setting I can change so I don't have to roll out the entire web application project - only the Utlity.dll? Thanks!

Solution

I modified the assembly bindings in my web.config file to fix this issue. I used the following examples that were already there:

<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>