I have a shared DLL that use across multiple ArcMap AddIns. It rarely changes, but recently I've had to modify it and I started getting MissingMethodExceptions whenever I made calls to classes in that shared DLL.
After some investigation, I realized that there are other ArcMap AddIns that carried an older version of the shared DLL that were being loaded first. And if I clear out all of the other AddIns and blow away the assembly cache, I run by AddIn with new Shared DLL with no issues.
Is there a specific order of AddIn loading from the assembly cache? In my case, it appears to be oldest first. Is there a way to alter the order of loading?