The application “League of Legends.app” can’t be opened.

I just patched LoL 9.11 and now when I try to open LoL it gives me the message, The application “League of Legends.app” can’t be opened. I'm currently on macOS Sierra 10.12.6. Do I need to upgrade to macOS Mojave? I have been avoiding this because I have heard the League Voice Chat stops working in Mojave.

There was a guide that was posted in 2013 that was very helpful in the past. Unfortunately, the package contents of the app are different now. You used to be able to just download the LoL installer then copy past the userkernel.app into your app's package contents instead of reinstalling the entire game. Now I don't see that in the package contents.

Please help! Thanks in advance :)