We’ve just been testing an upgrade our CMS and come across a few problems concerning newer versions of assemblies interfering with older versions stored in the GAC.
The solution is to use a binding redirect in Web.Config to tell the framework to use the latest version. For more info see Redirecting Assembly Versions.
2: <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
4: <assemblyIdentity name="Immediacy.Web" publicKeyToken="b35b2a186fcebe46"/>
5: <bindingRedirect oldVersion="220.127.116.11" newVersion="18.104.22.168"/>
To get the publicKeyToken for the DLL you need to open a Visual Studio command prompt and navigate to the folder containing the DLL and type:
SN –T assemblyname.dll
This will give you the publicKeyToken to put in the assembly identity.
Alternatively you could remove the old version of the DLL from the GAC by using this command with the Global Assembly Cache Tool
gacutil /u Immediacy.Web, Version=22.214.171.124, Culture="en",PublicKeyToken=b35b2a186fcebe46