Slitherine

I am sure the developers will appreciate your comments. I just want to mention that, during an upgrade, you usually don't need to worry about serial numbers for a previously installed DLC. If you ever looked in your C:\Program Files (x86)\Slitherine\Order of Battle - WWII folder, you may have noticed several text files that are named for each DLC that you have purchased. These files contain your serial numbers. (This is true for the downloaded version of the game. I believe, but I am not sure, that the Steam version does the same thing.)