Fixes a bug where the game would crash if you got the All Cured trophy at the end of year awards, when loading a save from 0.64 or earlier.
If you do not load save games from earlier versions there is no need to update.
Note:
CorsixTH-0.65.1-patch.zip contains only the changed files and can be extracted within an existing installation in the directory containing the Lua folder. If you do not know where your game resources are located, or are not comfortable working with files at this level, choose one of the other install methods.