Following Unity Technologies' guidance from October 3rd 2025, I am rolling out a COTLK build update to meet Unity's latest security standards. There are no changes to the game itself, it is a pre-emptive engine security-related update.
Because COTLK does not use any networking services or advanced features, this update is likely an overkill in this case. However, you should make sure that your Windows Defender and all your Steam games are up to date as they roll out in the upcoming days.