I ran Island Rum earlier today and it updated itself, loading islandrum-mac.zip. I launched the game and played a bit. When I tried to run Island Rum later today, I got an error message "You have OS X 10.10.5. The application requires OS X 10.11 or later." I could enter the game once more when I launched the CoH app directly, but when I tried to log in just a moment ago, I couldn't connect to server. The client was an old version and now it seems that I don't have means to update it.
Is there anything I can do to keep on playing in OS X 10.10.5?