title: ASP.net: Can I have 2 different versions of same dll/assembly in the bin folder?
body: <p>I am working on a large web application implemented in ASP.net. The main part of application, much of it implemented by a 3rd party, is managed by others so I don't have much control over it.</p>
  
  <p>I have implemented 8 ASP.net custom controls which compile to separate DLLs and are put into the application's bin folder. These controls have to link to a couple of DLLs (or should that be assemblies?) from the main application which are also stored in the bin folder. Let's call them <code>MainAppCore1.dll</code> and <code>MainAppCore2.dll</code>. These seem to be managed .NET code.</p>
  
  <p>My problem is that the main application has been updated, and worse looks like regularly being updated in the near future, due to to bugs problems I have compiled all my controls against the original version of the main app dlls, so now they won't load. Obviously I can solve the issue by recompiling all the controls against the new versions of <code>MainAppCore1.dll</code> and <code>MainAppCore2.dll</code> but am looking for a smarter way </p>
  
  <p>My question is: is it possible to keep <strong>2 versions</strong> of the main app dlls in the bin folder so that my controls will keep working (probably) each time the main app is upgraded?</p>
  
  <p>I don't want to have to edit the <code>web.config</code> file by the way as this would be politically complicated.</p>