Is this DLL getting built as part of your standard build process? Is the build done manually or is it part of a Continuous Integration process? How are you installing? Most installers allow you to flag a file to always be overwritten.

>You hit onto something. The interop DLL version doesn't increment and that's why it's not getting replaced. Would the only way to resolve this be to use TLBIMP to manually generate the interop or is there a way to automate the incrementing?