The .Net application with existing code using BusinessObjects.DSWS.dll of SAP BO 4.0 was working previously. In the existing code if the SAPBO code is called without any changes at application it was throwing "Login Exception" error post upgraded to SAP BO 4.3 installation .So latest version BusinessObjects.DSWS.dll(Version 18.104.22.168.66) has been added and build in 64 Bit application but getting error "Could not load file or assembly 'BusinessObjects.DSWS.BICatalog' or one of its dependencies. An attempt was made to load a program with an incorrect format "
So kindly update if there is dll or configuration changes to be done or any documentation for the same.
There were a number of changes in the .NET SDK between 4.0 and 4.3. Most notably, all of the security assemblies were replaced with more secure versions. So, code compiled with the 4.0 SDK will not connect to a 4.3 system.
Also, you can't just replace one assembly and expect it to work.
On your development machine, you'll need to uninstall the 4.0 SDK and install the 4.3 SDK. Then you'll upgrade your application to use the latest version of the whole SDK by deleting all of the references to the 4.0 SDK in your project and replacing them with the new assemblies from the 4.3 SDK then recompiling. I don't recall whether there are assemblies available in 4.0 that aren't available in 4.3, but that is a possibility. Other than that, a recompile should work. You'll then need to re-deploy your application, including uninstalling the old SDK runtime and installing the new one, which can be downloaded from SAP.