Why are there Different versions info for the same DLL?

Question

I recently had my first encounter with Could not use file or assembly version issue. And I had some understanding How and Why assemblyBinding>

<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-7.0.0.0" newVersion="4.1.2.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

But I am still not sure about the usage of other versions info?

Q:- what is the use of Runtime version(red box), the File Version(yellow box) and any other use of Green box?

Noob Q:- Why can't we have one unique version for each DLL?

score 1 · Accepted Answer · answered Jan 20 '23 at 14:52

what is the use of Runtime version(red box)

This is the runtime that will be used by this reference. This will always be 4.0.30319 for .Net 4.8 references, and any other .Net framework 4.x reference. Since .Net framework 3.x and earlier is uncommon these days I do not think this is very useful anymore. I do not think this is even displayed for .Net standard/core projects.

the File Version(yellow box) and any other use of Green box

The file version, product version, and version in the reference box, all uses different fields in the file. So there is nothing that says they have to be the same. But if you just create a regular library project and build a dll, the compiler should set all of them to the same value. It is usually fairly simple with pure .Net dlls, but other types of dlls can have different versioning practices to make things more complicated.

Why can't we have one unique version for each DLL?

I'm not sure what exactly you mean by this. But versioning is difficult. A common problem occur when libraries use different versions of a third library. It is possible the two versions are different in some regards, and any way you can handle this risks breaking something.

I would recommend reading John Skeet's article on Options for .NET’s versioning issues for better insight into the potential problems.

Why are there Different versions info for the same DLL?

1 Answers1